Can't sleep

So I post about some humiliating past experiences and when I lay down and try to sleep what happens? I think about those experiences and what I could have done different. I quit sports for the most part when I was 14, even though I had the ability and loved to play them. I quit because I was too worried about what everybody was thinking of me. And let me tell you, in case you forgot...those early teenage years are hell. Most of my "traumatic" humiliating experiences came from these years. It was a self-fulfilling prophecy. I was so worried of what everybody was thinking that I was dumb, that I blanked out and became temporarly dumb. I could not think. But I'm not dumb. It's just when I was experiencing a lot of anxiety.

Now why is it, that my mind is on overdrive while I try to sleep, but as the time approaches for me to get up for the day, suddenly it slows down and without effort, I finally drift off and I get a grand total of two hours of sleep.? My mind is not racing then. Why is it now?