In that case, start working on a contingency plan. Take anything you will regret breaking out of your room whilst you are in a good mood; tidy your space so that the mess doesn't get to your head. I don't know how you normally deal with your anger, but I listen to music and hit stuff. If you do this try to hit things that wont hurt you or get broken, like a pillow or your mattress. Also try writing down your thoughts when you are in that state, if you feel able. It might feel goofy at the time but if you can do it you'll probably get some sort of idea as to why you feel like this. I get similar mood swings (not as profound as yours mind), and actually just writing out this post has helped me, as its made me think about what is actually happening.
P.S. talk to your family! Unless you really do not get on, they will want to help you, and if you are hurting them they deserve to know whats going on in your head