I feel like I messed up a job interview that I had two weeks by saying something defeatist during the interview. It just slipped out.

I agree that we can give off signals when we are depressed, and it is just soooooooo hard to even get going for them. Mine was a whole-day affair of interviews, a luncheon, a teaching demo, and I almost walked out around noon saying "I just can't do this." But that would have been even harder than staying, so I did.

Best wishes with this. Give yourself a lot of credit for doing this while depressed, for even having the energy and will to line up three interviews.