Though my periods are on time, it started yesterday normally but today only the flow stopped completely. There is some problem for sure as the flow continues heavily for atleast 3 days every month. No unprotected intercourse, but there has been a weight gain of around 7 kgs in past 2-3 months. What can be the probable cause for this? I had an irregularity in menstrual cycle this january also. It was around 25 days late.