What is it?

So I'm on birth control and in the past 4 days I've missed it bout 2 or 3 times.(ik oops) I was in another state and yesterday I got back so of course me and my bf wanted to have sex. So we did. It started out with head and he was fingering me and then it started to hurt but not that bad to the point of stopping. Then we had sex. It was kinda sore afterwards but not too bad. So today I woke up feeling weird like my stomach hurt like cramps kinda and I was like let me see when my next period is. So its 11 days from today so I was like oh so it couldn't be that. So then a little ago my bf pointed out that I was bleeding and it was brown. Now is this from like damage and that's why it was hurting or is it something else?