What Causes Lower Back Pain,vaginal Bleeding And Abdominal Pain?

I had an incomplete medical abortion at the beginning of November and have since been back to the hospital for two check ups where I was told the products would reabsorb naturally. I started bleeding the week before Christmas having stopped three weeks or so after the abortion. I assumed this bleeding was a period and thought nothing of it however I have been bleeding since. The bleeding varies in quantity, from spotting to flooding. Now I am suffering from mild to moderate lower abdominal and lower back pain, my bleeding has lessened to a brownish red discharge which is foul smelling and I am concerned.