Many clots larger than half dollar coin, soaking thru ultra tampon every 30 minutes for several hours.

Excessive bleeding: Pregnancy should be checked for. Any gum bleed or excessive bleeding on minor cuts? Clots form if blood stays at one place for some time. Check for anemia, if hematocrit and red cell size low, check iron.if no irregular or after sex bleeding, only during periods without anemia or iron deficiency, you should be fine . See the gynecologist to look for fibroids etc.

Bleeding: If this continues for more than a two days at this amount or rate, I would want you to be seen to rule out too much blood loss. I would regardless make an appointment with a gynecologist to have this examined and see if you need to go on something to help slow this down and decrease the pain associated with the periods.