Scared

I met my boyfriend about 5 months ago. My mom just recently found out that I'm sexually active with him. I get that she is worried about my getting pregnant so she wants to put me on birth control. I can't be put on birth control because I have migraines and the doctors are worried that it can make the migraines come more than usual. We use condoms.. I'm scared to be put on birth control.. I don't want to have migraines.. What should I do? 
-age 16