Excessive Vaginal Bleeding while on Merina IUD

Patient: I am on the IUD Merina birth control and my boyfriend always uses a condom when we have sex. I was recently jumped and taken to the hospital. I was having vaginal bleeding and they diagnosed it as internal bleeding. My hips have been hurting and pelvic area inbetween my pelvic is in severe pain. The bleeding has stopped but the pain has not. Just curious on ideas on why i could be hurting.Thanks