Being safe

I am 17 and have been in a relationship for a few months now. I Im going away for the summer and I know I'm ready to have sex with my boyfriend before I go but the problem is my worry of pregnancy which I know is probably irrational but whenever I think about sex that's the first thing that comes to mind. My parents are quite conservative and I am not allowed to go in the pill. Sex is also something i couldn't talk to them about. I know about condoms and all the risks involved but I'm at a stage in my life where an accidental pregnancy would have terrible consequences for me. I don't really know what I'm asking but I guess I'm just looking for advise??