Blood clots! Someone help me

Very small blood clots are very normal for me half way through my period. I have very scheduled periods, this month my period will be here tomorrow (Wednesday the 6th) but 3 days ago I had a HUGE blood clot, about the size of a york peppermint patty, only after I poop. Does anyone have any idea what this could be? I am also have severe pain inside and out.