What Causes Early Periods After Taking Duphaston?

hi, my name is mado. i took some tablet last 2years to abort a month old prenancy, and it was successful but later i started experting irregular cycle, so i visited a doctor and he told me it was due to the tablet i took that causes the irregular menstruation, so he asked me to take duphaston tablet for 3 cycle which i did, but the following month i had my period a week before the normal date, please help me what should i do next. waiting for ur answer. thank you!