My boyfriend and I have been having sex for a couple weeks now and I'm on birth control so we don't use condoms. I was supposed to start my period three days ago (Sunday) but I still haven't gotten it and it's Wednesday. We decided to have sex on Tuesday since I still hadn't gotten it and there was a little bit of blood, but it's only internal. There is no blood coming out so I'm confused as to whether this is considered my period or not. I've never had one like this before, so should I be concerned about pregnancy?