Hello, I need help. As I was peeing just now, a brown clump of thing slipped out from my vagina into the toilet. It wasn't red or anything, just plain dark brown. It only happened once, my pee was normal every time after that. I haven't had my period since June, so I'm wondering if it could be old blood or something. I don't usually get monthly periods, they are very irregular for me, and my family doctor said constantly irregular periods are rare but normal. Is the clot anything serious?