I'm fifteen and have period issues. i really need help..?

Around a year ago I was having heavy and frequent periods with blood clots. They linked it to hypo-thyroid and I started taking birth control pills to regulate my periods and thyroid meds. I've been off birth control for about 6 months now and have had no abnormal (no blood clots, regular periods, not too heavy) problems but just now my period got very heavy (it filled a Super tampon completely within 30 min) and I had blood clots. I'm just trying to figure out if this is worrisome? Should I talk to my mom and doctor or is it going to be fine..?