Why am I having such a hard time sleeping?

I was sleeping really good until August of 2012. Right after orientation for school (I'm 16) and then I started having bad problems sleeping. Like I'd toss and turn all night and stuff then just be tired the next day. Then after a few months it got increasingly worse. I'd be up without sleep for a few days at a time and then I'd sleep for like a few hours (maybe 3-4) then be up for another few days.

It's rather frustrating if you could understand. Trying to focus on school work and tolerate people while running on NOTHING. Then I slept very good for about a week (about 10 hours a day) then I just snapped out of it and started not sleeping again this is like really annoying. Then before this (Around June or July of 2012) I was sleeping TOO MUCH. Like 17 hours a day. I couldn't stay awake. Any tips, or tricks/hints that would help? Btw I don't have health insurance till next month so try and suggest things BESIDES seeing a doctor.