OP, reading your post relieved me a bit. I think we both might be experiencing the same thing, or similar anyway. I thought mine was disassociation at first, but it seems to coincide with my depression. For example, when my depression is really bad is when I feel the most 'out of it' and I have to push through the 'fog' in order to function properly. I also only started having it when I started getting depression symptoms. When I was in school, it made it hard for me to focus in class, and I know I must have appeared 'drugged' to my classmates and teachers as well. I even slur my speech a little; I'm slow-moving and lethargic; I'm just not "all there".

I compare it to sleepwalking, in that I go about things normally, but I'm not present; my mind is elsewhere, wrapped up in its own blanket of fog. Sometimes I just can't push through the fog. Those are the times I get a bit scared, and I'll do anything to just 'wake up'. I want to be real and feel real things. I want to feel like my surroundings are real and solid, and not like my hand would go through the wall if I touched it. In that state, I feel like I'm not me, or anyone really.

Like OP, I never see this in any of the list of symptoms for depression. But I know that mine is part of my depression. I've read such feelings of unreality can be a result of trauma, which i've experienced, though not to a very severe extent (I've just seen and heard a lot of things that messed me up). So maybe this feeling is really the brain's attempt at coping, by 'removing' us from reality, though in the end it does more harm than good?

I'm sorry I don't have much in the way of advice. I just wanted to share my own experience with this 'feeling of unreality' and my relief that I'm apparently not as alone in this feeling as I once thought,