I know your feeling all too well. I could have been reading about myself in your post. I worked for the federal government for 23 years, became a team chief, and switched to a different profession at the same agency. At the end, my branch chief and team lead did not want me in the branch anymore. This made me more and more depressed and suicidal. Again like you I left the agency, on disability retirement, because I was afraid of being fired. It has been two years since I retired and I am still trying to pick up the pieces. My main bit of advice is to point out your former job is not you and you are worth much more than your former job. Do not give up depression can be conquered.