So I started my period a few days ago and last night I had an extremely sharp cramp that almost brought me to my knees. I sat on the toilet and was literally dripping blood like a faucet, so I wiped and on the wipe was a blood clot about the size of a 1/2 dollar coin with a piece of, what I assume to be uterine lining, about the size of a quarter and about 1/3 of an inch thick inside the clot. I've had large clots in my period for as long as I can remember (started my period at 13, I'm 20 now) but I've never passed a piece of uterine lining before. Not sure if this is normal or something I should go to the doctor for. I'm 100% definitely not pregnant.