What to do about my periods...?

I'm 16. I started when I was 12 and ever since I have had such bad side effects. I had headaches, feeling sick, feeling faint, severe stabbing pain, back ache, moodswings, constipation, diarrhoea, hot flushes, shivers, and exhaustion. I tried several different medications for this until I went on the pill as a last resort when I was 15. This improved for a good year or so but for the last couple of months these symptoms have been creeping back in. Would changing pill help? I can't stand going through this again. I missed school every month. Sometimes I can't help crying from the stabbing pains.