Birth control and parents! Help!

This morning my cramps were so bad I woke up crying and couldn't fall back asleep. I took my normal extra strength painkillers but like always it didn't help. I know that birth control would help by what my friends have told me about them taking it. I'm 17 and a senior in high school but my mother won't let me take it. She is extremely religious and she says absolutely not when I bring it up. What should I do?