If I'm pissed off, angry, sad, or even stressed out and I have no idea what's bothering me, I write a week biography about my greatness. Nothing too selfish. But all of my accomplishments. Sometimes being extremely self-centered can be good for you. As long as your not affecting anyone else. When I get the whole thing out I usually feel better. Sometimes it stresses you out that you can't help something or something is beyond your reach. Just write about it. Poetry is the best answer. You can tell people how annoyed you are and not even use complete sentences. There are no limits or boundaries in poetry. Just let it all out. When you're extremely emotional, you just need to let everything out on paper. Whether you're an artist, a singer, an songwriter, sculptor, or writer. Creativity is the key to your flow of emotions. Or something like that.
Hope it helps.
[P.S. Art isn't about how great your work is, it's about how intense the emotion is in it. Just lettin' you know. ;P It can look really bad to others, but if it's full of your feelings it's something special]