Period issue, PLEASEE HELP ME!!!!!!?

Well, I had a pad on, I slept from 1Am-9Am. I wake up. I sit up and I kinda feels like I'm peeing, like leaking. So I run to the bathroom and there is like 2 pounds of blood in my underwear. It stained my pants, and 2 pairs of underwear. I already had to throw away 3 pairs. Please tell me what Is happening