What May Cause Excessive Bleeding After Depo Shots In Anaemic Patient?

I had my period the 28th of June , it ended on July 6th . I had sex with my boyfriend unprotected on the 8th of July . Im bleeding worse than I was before and it started right after I had sex . and its now July 12th and I m still bleeding . I had a premature baby due to eclampsia on Nov 29th of 2013. i started the 3 month depo shot in feb of 2014 . didn t have a period in march but I had one in April , may and the first week of june 2014. I was suppose to get my next shot in may however due to having horrible side affects from the shot, I decided not to continue with the depo . so my question is , do uu think maybe I should go see my obgyn . could there be something wrong ? Or is this normal after birth control ? Help please . oh! And I am anemia.