What are these large blood clots? Possible miscarriage?

Just a very heavy period. I've had those before. Painful cramps until a clot comes out. Ew! I do something strange and funny in the shower.. I cough and spread my legs so most of it come out. LOL! Sorry, I just get fascinated by the little things. I suggest you don't use a tampon, just let it flow and come out. Just use one for overnight with an overnight pad. Hope it helps!