Regarding feeling like a fake at work: many years ago I was new in my career and had been promoted to being a manager. In a meeting with my (awesome) boss one day, I told her I sometimes felt like I didn't know what I was doing. This woman is one of the most competent, well respected people I have ever known. She looked at me and said, "you think I always know what I'm doing?" I was shocked to learn that she did not. She just did her best and figured it out as she went along.
When I feel like a fake at work, I often remember that conversation. I know things are much harder with mental illness. But, I don't think everyone we work with is necessarily more competent than us, or that we are faking our competence. If we are getting through the day and getting our work done, that is real.
I hope this makes sense.
I'm sorry you are having such a hard time, Hopeful Camel. Hang in there!
SA