I give this tip to people because it worked for me. When I was in my early teens I had hella hard times falling asleep. I'd lie awake for up to two hours staring at the ceiling above my room.

The solution was that I started listening to music/the radio every night when I went to bed. (Or if you like to read get a few of those recorded books lol) A few months later I started to fall asleep easier, in around 30 minutes to an hour. Now I don't even need the radio anymore.

It could just be a phase we all go through where your metabolism is too high or something. But listening to stuff really helped.

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And also yes, there are different levels of insomnia. Serious insomnia leads to sleep deprivation which can cause death and extreme fatigue.

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EDIT: Oh yes on the original question. Just don't stay up long. Get up, open your window. Do something menial. Then go back to bed. If you wake up way earlier then you are used to you won't have any trouble getting back to sleep.