I've experienced it a lot without knowing what it is as a kid and it was always very short, but in high school I started to read about it and I've learned that i can "force"... I used alarm clocks, I would wake up in the middle of the night just to go back to sleep and I would do that repeatedly.. it actually works :) I also did stuff as counting my fingers every hour but that didn't really help me. I also listened to some music on yt and that was also pretty helpful