If you notice your toddler snoring or breathing noisily with an open mouth at night, Nevares says this could be a red flag sleep apnea (which is different in toddlers than adults).

"This type of noise signals some type of trouble (in their airway) and should be recorded and reported to your child’s pediatrician," sleep consultant Tonja Bizor tells Romper.

Waking up throughout the night can be normal, but if your toddler is waking up frequently, you may need to look further to see if a problem exists.

"We all actually wake up many times during the night as we cycle through various stages of sleep, but we should be able to roll over and fall back to sleep without even registering that we were awake," pediatric sleep consultant Jamie Engelman tells Romper. "If children are waking frequently and up for prolonged periods (or need assistance in falling back to sleep), it could indicate a lack of independent sleep skills and/or a scheduling issue (such as too much or too little sleep during the day)."

"Just like frequent night wakings, long night wakings can be a symptom of needing more sleep, not less," Lynelle Schneeberg, Psy.D., pediatric sleep psychologist, author of Become Your Child’s Sleep Coach, and director of the Behavioral Sleep Program at Connecticut Children's Medical Center, tells Romper. "Look at your child's overall amount of sleep and consider putting your child to sleep earlier, rather than later."

Does your toddler fall asleep in the middle of doing things throughout the day, even when it's nowhere close to nap time? "A person that is resting well at night and getting proper nutrition should not fall asleep frequently during the day," Dana Stone, infant and toddler sleep consultant, tells Romper. "Excessive tiredness on a daily basis can be an indication that even though it may appear someone is sleeping, they may not cycling properly through the stages of deep sleep. This can be easily reviewed with a sleep study."

It's pretty startling (not to mention frustrating) when your toddler wakes up scared in the middle of the night with a nightmare or a night terror, one of which could signal a sleep problem.

"[Night terrors and nightmares] are not the same thing. Children have bad dreams from time to time, but if they are so upset, inconsolable and don't seem to be awake, it could be a night terror," children's sleep consultant Christine Stevens, tells Romper. "Children are likely not to remember that they had the dream, whereas with nightmares, children will usually be able to tell you they were scared of something."

If you notice your toddler moving a lot while sleeping, it may be a red flag, but not always. "Kids are very restless sleepers. If combined with sleep-disordered breathing though, then there is cause for concern," Schneeberg tells Romper.

"Extreme restlessness can be a symptom of RLS (restless leg syndrome) [which] can affect one's ability to fall asleep and stay asleep comfortably," Stone says. "Usually, it's described with an uncomfortable sensation in the legs. This can be aggravated by overexertion and exhaustion."

If they're "falling asleep the instant they are in the car or moving stroller," that's a sign your toddler isn't getting enough good, sound sleep at night, Ancy Lewis, LCSW-PC, of Sleeping Little Dreamers, told Romper for a previous article.

I have experienced this red flag with my own son as a toddler and it took a while for him to overcome his trepidation over going to sleep. "This almost always means that a child can't yet self-soothe,” Schneeberg tells Romper, and the child will be uneasy around bedtime because the parents “may or may not be willing or able to stay nearby until the job is done.”

In addition, genuine angsty and dread, with real tears, at bedtime or in the middle of the night — where it’s clearly not manipulative behavior — “is generally a sign that your child is processing something that they learned during the day," says Nevares. "It could be due to moving homes, starting school, a new teacher — or simply a story they heard from another kid.” Processing all of this “is a healthy part of psychosocial developmental, and phases usually pass within a few weeks,” Nevares says. If these concerns “persist, or if your child says or exhibits that they're scared of a child care provider or family member, that could be a bright red flag."

I grew up with a sister who was a sleep walker, and it was definitely a scary experience, but working with her pediatrician helped solve the issue. "Children who sleep walk get out of bed and walk around without waking up," Bizor tells Romper, and the child could end up “falling down the stairs, leaving the house, etc.”

Therefore, Bizor says, “do not wake the child by shaking or shouting at them.”

In addition, sleepwalking “could also be a result of sleep deprivation,” Bizor adds.

It can be tough to figure out what exactly is freaking them out when your little one is crying for you to stay in their bed (or not to leave yours), but it's important to make the distinction between genuine being afraid of going to sleep and a dependence on a caregiver to fall asleep, Nevares says. If a child hasn't been sleep trained, being afraid of sleep is likely to be a behavioral issue, she explains; if they have, it's more likely to be genuine versus anything from potential real physical harm to monsters in the closet, which can be a normal developmental phase.

Consider your own emotional state when a certain toddler has meant you’ve gone without sleep for months on end and it's not difficult to understand why an overly emotional toddler might be a tired one, at heart. “A normally easy-going child might suddenly burst into tears, [have] a tantrum, throw their sippy cup at the dog, or flat-out refuse to (fill in the blank)," says Nevares.

One surprising and common behavioral change for a toddler who doesn't sleep well (as a one-off or on a regular basis) is that they might rarely look obviously tired, Nevares tells Romper. "Ever seen a toddler running around at 8 p.m. even though they've been up since 5 a.m. and refused a nap? Ever been so exhausted, yet you can't sleep? That's adrenaline," she explains, or what you might call a "second wind" (or third, or fourth).

While exhaustion might turn toddlers into unpredictable nightmares in some ways, "if a toddler isn't regularly sleeping well due to learned behavior, then daytime behavior is usually fairly consistent," Nevares says: stereotypically willful and boundary-pushing, the type of thing that often gets a kid referred to as a "spirited" toddler. "Gifted with extra adrenaline, these tired toddlers might fight sleep for days, then suddenly doze off in their high chair," she adds.

Some red flags are more entertaining than others, but it's still worth taking notice if your usually somewhat serious tot is suddenly "more entertaining and goofy and silly and hyper," Angelique Millette, Ph.D., told Romper for a previous article. For some reason, some kids "become more entertaining and become party kids as they become sleep-deprived," she explained. (Just be sure to get some good video of the sleepy sillies before getting their schedule on track.)

The vast majority of the time, a toddler insisting for midnight drinks and snacks is probably stalling. But it's also important to pay attention to other physical symptoms, and trust your gut. Nevares tells the story of one 2-year-old girl who refused to give up nursing around the clock; even changing her dependency on nursing to sleep didn't stop her from waking up hungry. "Fast forward several months, she was diagnosed with Celiac," Nevares explains. "She was genuinely hungry because her body wasn't absorbing any nutrients."

If your child struggles to fall asleep when they should be tired (like after an active day at the park or the beach), this could be cause for concern, but it could also just be a sign that they are overtired.

"There are many reasons for this stemming from scheduling issues to environment to temperament and stress," Engelman tells Romper. She recommends making sure that your child isn't exposed to "excess light or screen-time during the hours prior to or at bedtime" and to "use a calming bedtime routine and practice relaxation techniques to help calm the child's mind and body" if stress is the culprit.

Believe it or not, a well-rested toddler shouldn't need an alarm clock.

"If you have to wake your child to get up for school or child care, then your child isn't getting the sleep that she needs," Dr. Jodi Mindell, author of Sleeping Through the Night, told Today. "Figure out how much sleep your child needs, and count backwards from what time she has to get up in the morning. This will help you determine what is her ideal bedtime."

If you feel like you have a small human covered in suction cups somehow attached to you at all times, it could have less to do with their personality and more with their tiredness levels. Both clinginess and increased dependency can be signs of exhaustion, Dr. Marc Weissbluth, author of Healthy Sleep Habits, Happy Child, told Today.

Toddlers shouldn't be "catching up" on sleep over the weekends like adults, both Dr. Mindell and Judith Owens, M.D., M.P.H., Director of Sleep Medicine at Boston Children's Hospital, told Romper for a previous article. That would mean they lost sleep at some point during the week, and that's not good for toddlers (or anyone, really).

It's not uncommon for even toddlers with perfectly health sleep regimes to put up a fuss over the prospect of a nap (and/or bedtime, depending on whether or not they've given up napping), but it shouldn't be an all-out issue every time, Dr. Millette told Romper. If they’re fighting you on sleep every time for a month or longer, it might be time to talk to your pediatrician.

Experts:

Natalie Nevares, sleep coach and founder of Mommywise

Tonja Bizor, certified Sleep Sense consultant and owner of Tonja B's Sleep Consulting

Jamie Engelman, MS and Pediatric Sleep Consultant with Oh Baby Sleep Consulting

Lynelle Schneeberg, Psy.D., pediatric sleep psychologist, author of Become Your Child’s Sleep Coach, and director of the Behavioral Sleep Program at Connecticut Children's Medical Center

Christine Stevens, children's sleep consultant and owner of Sleep Solutions by Christine

Dana Stone, infant and toddler sleep consultant with Rest Assured Consulting