Stress

I'm stressing myself out (I hope) and worrying too much. I know it's my fault so don't bring out the "use a condom next time", I got with this guy last weekend and I'm not sure if he came in me or if it was me. I'm 17 and I've been feeling really off since then, I dont think I'm pregnant but i'm really stressing myself to the point where I'm beginning to think I am and I can't say anything to my parents about it. What do you guys suggest?