Bleeding during sex

I need help with something. Me and my boyfriend were having sex and I was on top and all of a sudden he says "are you bleeding?" And as soon as I looked down I saw blood all over him and the condom. I'm so scared and embarrassed that this happened. I'm not on my period but I am suppose to start soon. Can someone tell me if this is normal or if they've experienced the same thing? I need some reassurance......