HI IAM26 YEARS OLD AND MARRIED FOR LAST 4 YEARS. AM ALWAYS MISSING MY MENSTRUATION (3 - 4 months i dont have menstruation)WHEN I GO TO THE DOC HE GIVES ME PROV-ERA TABLET S AND AFTER TAKING FOR 3 - 5 DAYS I HAVE MENSES BUT ITS DOESN'T COME THE NEXT MONTH AND I DON'T GET PREGNANT AS WELL THOUGH I NEVER USE PRECAUTIONS OR ANY TABS. I HAD MY PELVIC EXAM EVERYTHING OK.IAM REALLY WORRIED CAN SOME PLEASE ADVISE ME WHAT TO DO.