HELP! What is this?!!

I was having cramps all day yesterday (a bit worse than usual) and I went to the toilet & I felt something kind of ‘fall’ out when I wiped.

I’ve been having periods for 10 years and have never had anything like this before. I’ve had clots of course but nothing this bad. Does anyone have an idea would it could be?

The grey bit at the top looks more thick and veiny in person 😬 Sorry for the images I’m just really confused and need to know if it’s happened to anyone else before.