Blood during sex???

So basically I ended my period like a week ago and so yesterday My bf  and I were doing the do. we finished and I look at my hand and it is COVERED in blood. Not like a period amount, but like drenched. I was bleeding and like we both started worrying about what it could be, because I know my body and this was not normal. so we got in the shower and I stopped bleeding, and we both were freaking out because I wasn't in pain or anything and He kept asking me if I was okay (and I was fine) but I was just over come with emotions and wanted to cry bc something felt wrong. we tried to google what happened and people have had this happen but there were no explanation. ANY advice? Has this happened to you? What do you think it could be?