I get the bit about the two halves of your mind arguing with each other, I have that a lot. Sometimes a third part would be useful because it could yell "shut up both of you & leave me alone".
The common perception of depression is of a "soft" mental illness which isn't too serious, people often forget that it can present with very serious symptoms, so I'm inclined to believe that the symptoms you've described is probably a manifestation of your depression, especially as you are having sleep problems.
Sleep deprivation makes me psychotic in that I hallucinate, and the things that I'm scared of in dreams then start to occur in hallucinations too, there is no escape either asleep or awake. I just hate that.
There is a really interesting guy on PC called Thunder Bow, he does dream interpretations, if you think it might help, have a look at the sleep and dream forum.
If it helps you to vent here, vent away, there's usually someone around who can identify with your feelings without being preachy.