Awww. you poor sweetie. My sympathies, I've been in this situation.
Go to see Mr/Ms Doctor (GP) - there are tabs they can prescribe - ponstan for example (mefenemic acid) which reduces the spasms and pain. Exercise also helps, but it needs to be quite ungentle - like 10 lengths of the swimming pool doing the front crawl - kill them cramps hehe.. A hot water bottle was very good for me, so long as I was gonna be sitting still or lying in bed...
Good luck sweetie, hope you get it resolved..