Nose won't stop bleeding/producing bloody mucus

About 3/4 days ago, I started producing hard, bloody mucus in my left nostril. When I blow my nose, I get a decent amount of little pieces of blood and mucus. Every 6 hours or so, I get a big "blood clot" (not sure if thats the right term, but thats what it feels and looks like) that is really dense and kinda dry, almost crust-like. I looked in my nose with a flashlight and I can't see much but see a thin layer of blood far inside.

Don't know what to do or how serious this is.