I agree with all of the above. I had a couple of good days - thought my meds were finally starting to work - then BAM, as you said, depression hit me like a sledgehammer. It is very frustrating and make me even more depressed when I think I am getting better only to find out I am right back where I started. I know my T must get tired of hearing about it from me (and probably from everyone else). From what I have read, major depression and anxiety are like this - from feeling good to being slammed from one moment to the next. It has even happened to me in his office.