Period got me home again

Does this happen to anyone else? 21 days out of school now all because of period cramps. They got me in so much pain I get goosebumps and start to shake. I get nauseous and throw up, and major diarrhea to the point were I didn't even know there was still stuff to come out! So much pain I'm lying there praying that it will stop. Can someone please comment something, either similar experience or advive?! My doctor won't belive me even tho I swear it's ulcers, she says it's possible but we'd have to do a scope, AND NOT EVEN IN MY UTERUS. IN MY STOMACH! Like what?! Just someone please help I'm crying right now.