Go to sleep much earlier, like before midnight. Not only should you find it easier to fall asleep after a few nights but you'll also sleep better, wake up early and have a full day ahead of you. I used to fall asleep at 4-5am because I didn't feel tired, I'd sleep till 12 or 1pm, more often than not have a bad night and wake up tired. After a few days of forcing myself to go to bed no later than 1am, suddenly I had no problems with falling asleep and having a good night.