Right now I'm so tired I could knock out,but I know I'll wake up way too early, so I make myself stay up... but by the time it's later (10 or 11) I can't sleep for anything. I won't end up falling asleep until 3am or so... it's really screwing with me.. why am I like this all of a sudden?
If you can avoid sleeping pills, you should. They may make you sleep but they generally dont give you the kind of sleep that makes you feel really rested. I have the same problem alot of the time, mostly because I just cant stop thinking! I find its good to get a bed time routine going, for example, I usually have a cup of herbal tea with my flatmate, take out my contacts, brush my teeth, wash my face, then read for a bit. I try not to do too much of my course work too late, or I find I stay up and think about it for ages. Unless its really boring stuf, that always seems to induce sleep.... Anyway, I find a regular bed time routine helps me to switch my mind off and get to sleep.
Try taking some sleeping pills.
Or have sex, work out, go for a walk, clean until 10ish then try going to sleep :]
Tire yourself out before going to sleep :D