sleep troubles

I'm a student who has school everyday at 7.30. For the past one and a half year, I've had a really bizarre sleep schedule that probably can't even be called a schedule.

Something to note is that I'm an extremely heavy sleeper. Alarms have never worked on me and the only way I can wake up before I get enough sleep is by someone shaking me awake.

When this first started, I was having trouble falling asleep. It was like that for a few months and every morning my parents had to literally drag me off the bed. Then at some point I managed to start falling asleep earlier, except for the fact that I was waking up almost every other hour. Then I went back to having trouble falling asleep again after a few months. A two month holiday came and I started falling asleep between 4 and 6am, only waking up past noon. By the time the holiday came to an end, I realised I had to do something so I stayed up all night, making myself naturally fall asleep around 6pm, so I would wake up before 2am and be awake in time for school. Since then, I've spent several weeks alternating between having difficulty falling asleep and waking up constantly. And then after several weeks I'm back to sleeping early.

I've pretty much learnt to deal with working around my schedule so I won't be late for anything but it's still kinda frustrating. I've done some research on sleep disorders and apparently I show symptoms of insomnia, dspd and aspd?? Does anyone know what I can do/what's with my sleep schedule?