no pain, but lots of bleeding during sex

Well, yesterday I was quite worried because I was having sex with my boyfriend. I haven't been a virgin for 3 years. When I had an orgasm I reached down because it felt like more than usual, but when I pulled my hand to look at it, it had blood all over it. I got off of him and blood was pouring off of him. I was runny blood, not like when you have sex on a period. It looked as if I had peed on him, but it wasn't pee, it was all blood. My boyfriend looked at me and he said it was comming out from my vagina. We were well lubed so it wasn't tearing anything. I'm not supposed to have my period for another 2 weeks. I have been on some type of birth control since I started having sex, but I do not always use condoms. I have been with my boyfriend for two months. I have been tested a few times for diseases to be safe. This is the first time this has ever happend to me. What could this be? Please get back to me.