I actually have had issues with this all of my adult life. Diagnosed about 8 years ago when couldn't get pregnant. I didn't have a period for over a year and a half and within the first month, started having them again. No BC being used, down 90 lbs and no such luck, but they are started again. I was taken off of the glucophage when I had the surgery and haven't taken since. I am also hypothyroid and on a very small dose(less than 1/2) than before surgery,so I think it all works itself out with the weight loss.
Good Luck!! Ask any questions that yu may have