@bittersweeet, mine stopped at one point for 2 full years, turned out it was related to other medication that I was on.
Are you on anything, prescribed, vitamins, supplements, diet plan, illegal substances, heavy alcohol or binge drinker? Just trying to put it together.
Is your BMI healthy? if you are underweight or obese, it can also affect them to the point of stopping.
Are you having any pelvic pain, other symptoms, any discharge? Any other symptoms tender breasts? (although you know you aren't pregnant), nausea, bloatedness,
Also keep a list of all symptoms (otherwise) for gynae, I know how it is as my periods over the past 4 years up until May this year, were all over the place, I was having 2 a year at most, then it regulated itself, with no changes being made (my weight was the same, meds were the same, I need them on a day to day basis)
Also when I would be willing mine on, sometimes I found if I went out of the house for a walk with white jeans/trousers on, it would come - black jeans/trousers didn't have the same effect but the white always seemed to get stained whereas black/blue didn't. Sod's law
Good luck and hope the gynae is helpful