Anger

Sometimes I want to hurl my cell phone across the room to watch it shatter into a million pieces.
Sometimes I wonder what it would be like to drift into the oncoming lane.
Sometimes I cut myself and wonder how it happened.
Sometimes I hit my pillow.
Sometimes I give in to road rage.
Sometimes I get the urge to hit something.
Sometimes I bite my finger and wonder if I'll puncture the skin.
Sometimes I drive fast because I'm angry.
Sometimes I think how stupid I am for doing this.
Sometimes I forget what I am.

What the hell am I?