How Can Menstruation Be Regularized?

hi. i had c-section before 9 months. from the 5 month bleeding is there for every 15 days. 5 and 6 months i had this period only for 5 days. after that it is there about 10 to 12 days. after 3 day period come for the 15 days calculation. i went a gynaecologist. she recommended a tablet to regularise it. i take this for 2 months. but even now it is about 10 to 12 days only.please help me.