Birth control talk

I'm 18 and I have horrible periods. I have two weeks of cramping, headaches, and nasea, and that's just my pms. I then get my period and my cramps intensify and I bleed for 7-9 days. My cramps are so bad I will have to stop what I'm doing and literally drop to the featal position. I tried to talk to my mom about birth control to help lessen my symptoms, but she doesn't seem very open. She mentioned she had bad periods and she could deal with so can I kinda thing. I'm in so much pain for most of the month and I don't know what to do. I'm scared to go down to planned parenthood to get it myself? Any advice???