Talking to my mom about Birth Control

Sydnee
So my mom doesn't want me on birth control because she thinks I'm having sex and doesn't want it to be an excuse for me to have sex. However I need it because my period are always late then really short when I have them and I have abnormally bad cramps, I swear I'm not exaggerating. Problem is I don't want to go to the Gyno and them ask me if I'm sexually active because I am and I don't want my mom knowing yet. I'm stuck and I don't know what to do.