Madam/sir,next Month First Week Fixed My Marriage.menstration Date For March

Madam/sir,next month first week fixed my marriage.menstration date for march 28.so i conuslt a doctor.she prescribe tab.meprate twice a daily for 5 days.taken tab meprate.april 15 to 19.but i confused my this month period date.so this tab.course finished,any chance for bleeding occur before april.26.kindly reply madam.if not get bleeding date of 25th.what i can do madam.