Recently I've started having stressful, angry dreams about the stupidest things. My heart's been racing when I go to bed and I can't find a way to be peaceful.

During the day I'm just peachy, no problems and not emotional or moody. It just seems to come on at night.

Has anyone else experienced this? Is it a symptom of pregnancy, or something else? As far as I know, there's nothing bothering me in my everyday life.