A grayish piece of tissue with like "balls" or clotted tissue at the end, that passes from the vagina, and associated with sharp cramps. Miscarriage?

Maybe. If you've missed a period and had a positive pregnancy test, then it's a miscarriage. If it comes when your period is expected, then it's probably something called membranous dysmenorrhea, meaning painful period with part of the lining coming out intact.