Insomnia is said to be present when you regularly find it
hard to fall asleep or stay asleep. It has several patterns.
You may have trouble getting to sleep initially. Or even if
you can fall asleep, you might not be able to stay asleep
for as long as you would like. Also you may wake up
during the night and not be able to go back to sleep for a
long time. Many people have two of the above problems,
or even all three. Because of these, you might feel tired
during the day.