TMI what are your thoughts? Could this be the product of a miscarriage?

TMI but advice needed. Could this possibly be a miscarriage? It came w/  the most unbearable cramps&super heavy bleeding! For the 12 years I've had periods, theyve never been late, never lasted longer than 4 days & NEVER has had clumps of anything in it. Advice? Opinions Anything is appreciated!