Kinda like when I got my first period... Except, well, y'know, blood came out of another hole and I wasn't swallowing it. But yeah, pain, nausea, feeling faint and miserable and thinking you're going to die. If you ever wondered how the first period feels like, that's it, but it goes on for a week or more and you can't cauterize it. Glad you're feeling better, OP.