How did you recover from a toxic work environment?

I'm currently on the job hunt but only because I was forced to leave a fairly toxic environment and left in a less than positive situation.

Since then my confidence has been damaged and never fully recovered despite taking time off, so much so that it's affecting my job search. I don’t feel confident that I can deliver good work when I rejoin the workforce and it's causing some anxiety when I apply for roles. I feel like I have the credentials and work to back me up but I currently just don't believe in them.

Have you ever been in this position and how did you recover or even simply cope with this new mental normal?