Sex started my period TEN days early

So I was with this guy. I had no spotting, bleeding, weird discharge, none of that. He comes over and fingers me. It was great but I didn’t finish. We had sex, he cums but I don’t. We had sex a second time a couple minutes later and everything is great until he flips me over. Blood is everywhere. Nothing was hurting despite him being larger. But I was bleeding really bad. The bleeding gradually slows but it’s like I have my period now... what is happening