Horrible pain!

I need some help! My period keeps changing days every month. I get super nauseous. Get headaches, backaches, and cramps. Sometimes I even throw up and get a bit dizzy. It all gets to a point where I can’t even get out of bed and I leave school ( I’m 16 ) and i know it’s a horrible experience for everyone but It gets super bad for me! Anyone know something that can help?