Talk to Gynecologist on Irregular Periods After Miscarriage

I had my miscarriage in second month of pregnancy and had d&c on 26 november. I had my first periods after d&c on 17 december till 26 december now i had my second periods on 9 january and still i am having spotting . Today on 19 january i had spotting with few blood clots. Why is my period cycle still so prolonged and why i am still having clots after so long period days. Also i have heavy bleeding in first two to three days and a sharp pain. for how much time i am going to have irregular periods? Previously i had a seven day cycle