I can't sleep ! ]= HELP ME?

Its now 2.28 am and I'm still not asleep. It's really annoying because I'im very tired but when I lie down and try to sleep I cant because im unsettled. I've already tossed and turned for about 2 hours. Ive tried watching something boring on TV, reading a book, listening to music. But nothing is settling me. I took a sedative before. And nothing. Im stressing out about not being able to sleep. Can someone think of something i can do?