Hi, it sounds like you have quite a bit of anxiety that accompanies your depression. It's not really all that surprising though, that you would feel like you're constantly second guessing yourself, or experience a rush of anxiety during job interviews. I'm not a mental health professional, but in my opinion, you need some POSITIVE experiences to make up for all of the crap and hardship you've had to go through during the last 8 months. You feel full of doubt in your current job, and that feeling of inadequacy probably comes out during the interviews. Every time you get rejected for yet another job, it reinforces your feelings of inadequacy.
Think back at the last time you felt competent, confident, and good about yourself. What were you doing? What did you wear? To whom did you talk? Is there some way you can re-create some of those positive past situations? Try to make yourself look as good as possible (as this will increase your confidence as well as the way others, maybe interviewers, will react to you). Try to look at it a little bit like a gamble: Apply to jobs you would not even really want, just to see how you can handle an interview without any stake involved. Besides looking good, also put on a very slight smile (just enough so that the corners of your mouth are pointed upward). Keep smiling even when no one is looking. Remind yourself that you are worthy, and that absolutely nothing can harm you.
I can understand how your self esteem must have suffered during these past few months. I also get these kinds of rushes of anxiety in similar situations very frequently.
Good luck to you.