Suggest Treatment For Irregular Periods

Hi ..my periods were always normal occurring after 28 days till i turned 40 and the the nightmare started.periods started coming after 17 days.Now am 42 and the problem still exists. consulted a doctor who put me on meprate 10 mg for 21 days for 3 months.The first two months were fine took meprate for 21 days and within 1 day periods started,but the in the 3rd moth i took meprate for 17 days and on the 18th days the period started.The doctor told me to stop meprate. The periods are heavy...not sure if i was on the right treatment...why did the period start after 17 days while i was taking meprate...Pls advise what to do...