I've always had trouble falling asleep and staying asleep, too.
My mother said that when I was about 3, she couldn't get me to so much as go to bed before 10 pm or so, and even after that, it would take a good hour to have me fall asleep --an hour spent discussing the weirdest questions, reading stories, falling asleep while reading (she would fall asleep, not me), and so on. And then I would randomly wake up in the middle of the night.
By the time I was in college, my schedule had switched to going to sleep around 3 or 4 am, and waking up around 1 or 2 pm (don't judge me, but you should have seen the look on that professor's face at a 4pm class I ran late to when I apologized for oversleeping).
Even now, if I'm left to fall asleep naturally, it won't happen before sunrise. I do blame my messed up circadian rhythm to some extent, but there's also the fact that nights are pretty much the only quiet time, so I enjoy being awake, and I'd much rather sleep through the noisy, hectic daytime. Sad thing is, I need lots of sleep, and even the most minor sound will wake me up.
Medication has never helped, from whatever I was prescribed aged 8 to various types as an adult. I was put for a few months on something to fall asleep coupled with something to stay asleep, and the only thing that ever happened was me feeling that my body was going numb, but remaining wide awake, now terrorized that I was somehow paralyzed and floating between awake and asleep.
Melatonin does help me get some better sleep, with less interruptions.
Oh, on a side note: I don't feel I'm on a 24-hr rhythm, more like 27 to 30 hours. Makes it even harder to stick to a proper schedule... Anybody else ever felt that way?