Suggest Remedy For Continued Bleeding After Placenta Removal

hello, im 19, female, i gave birth on the 4th aug 2009 and on the 12th november i got rushed into hospital as i didnt deliver my plecenta fully and since then iv been having periods 2 days of and 5 days on. ive been tested for std's and thyroid and i have been on tablets to stop my periods but it only lasted 7day, can u suggest anything that may be causing my periods. many thanks chantel keating