Raymond Pert of Kellogg Bloggin' wrote about fog (January 29th post). I tried to leave a comment, but my browser is blocking me AGAIN! (sorry about yelling)
This is a great explanation of mental "fog" that explains what I go through. Mine may complicated with the MS "fog" (and my friends tell me it's also age). All I know is that I have it, and it's miserable to deal with. It's a juggling game... what meds cause depression, what meds help, what side affects are bearable, reduce this one, increase that one.
And no... I am not sad! It's a brain chemistry thing, not a mood thing... And, I do know about moods! I'm in a bit of a cranky one now because of my PC troubles.
Anyway, click on the above link and read the post. It was very enlightening to read his explanation.