Help I need advice

I am 15 and me and my boyfriend of 1 year are at the point in our relationship where we wanna get sexual. We both have no way of getting condoms and my mother is extremely religious and didn’t have sex till she was married. I have had really bad period cramps and boob problems so I went to the doctor and me and my mom had the birth control talk and will not let me get it. Idk what to do or how I could get birth control behind her back. And he won’t get his license for another 8 months. What do I do?