I get this problem too, I have Insomnia and all so yeah. I just can't sleep sometimes. On my Birthday (well the night before) I got no sleep, nether did I get any the day before.
I can't sleep at all until like, four or five AM. Hopefully I'll be able to get to sleep tonight though... I wish I was at my boyfriends house, it's so much easier too sleep at his house...
But yeah. I need help too, sadly I can't do the masturbating suggestion as I can't masturbate well, and sexual activity usually wakes me up... sometimes it makes me tired, but not all the time.