ELI5: Explain Like I'm 5

insomnia

Insomnia is a problem that some people have trouble falling asleep or staying asleep, and it can make it hard to get enough rest. If you have insomnia, it means that it’s hard for you to take a nap or to stay asleep for the whole night without waking up too early. It can also mean you don’t feel rested during the day, even after you do get some sleep.