Regular then irregular

I have had a regular period since I have started my period when I was in high school. Even when I got on birth control I was still on the same cycle with the same amount of bleeding. But now this month it's day 7 (which normally is the end of my period) and I am still bleeding semi-heavy, but normally by this point I would be done  bleeding all the way. I was wondering if this has happened to anyone else, and what were the end results if so. Or do you think I should talk to my doctor?