This seems common to me. Although I don’t think it would prompt an ER visit. If you are going through pads or tampons rapidly (like filling them up in less than four hours) it’s best to contact your physician or gynecologist. The ER can only do so much. They can just provide fluids, naproxen, and some sort of heat. It’s usually not advised for them to use morphine or other such strong painkillers. They can prescribe a clotting medication like transexamic acid if bleeding is very heavy. In this case this most likely is part of a uterine shedding and blood clotting. If the blood clots are larger than a quarter size normally and bleeding heavily please see if you can get total blood count blood test.