Aww i feel for you!
Yeh, i hardly ever got ill and the only time i had off was for my period really! I didnt get pain until i was around 14, it was bearable at first at school with painkillers but gradually got worse and worse, by the time i reached 16 the pain (in my back) was so bad i fainted once and threw up a few times. The really horrendous pain like this would only last for like an hour and then the painkillers would kick in, but i would have a bit pain (bearable, like when 14) for like a day and then a lasting ache (from thhe pain for another day or so). Was horrid. This really bad pain only happened once every 2-3 periods, but i would always get some sort of pain.
Eventually i went on the pill and it helps so much. I still get back pain sometimes but nowhere near as horrendously. I would suggest going on the pill if you can, it helps me immensely! I wish I'd gone on it sooner.