birth control?

So I'm currently 17 and will be 18 in October. I've been sexually active with this guy for awhile now and we use protection and are really safe about it but there is always that think in the back of my mind saying something is gonna happen since I'm not on birth control. My parents are very religious and believe in sex after marriage so they have no idea that I'm not a virgin and will not agree to help me with anything like that. Can I get the pill without them knowing about it? I just want to be very responsible about everything cause I do have plans that don't involve a baby now