Hey. I don't have much advice as I have always worked, but I wanted to wish you luck.
Anxiety isn't logical but try to remember that spending endless energy agonizing over what horrible things could happen reentering the job market will not prevent them from happening.
In your mind, the worst has already happened, so whether you succeed or fail, you have already experoenced what that would feel like in your head repeatedly, so why not actually go for it in real life? Ido if that makes any sense. But for me, I often fantasize about and suffer the worst possible scenario in my head over and over. Back When going back for my MS part time I bemoansd to a friend that it would take me 5 years and I would be 35 when I graduate. She replied, u will be 35 in 5 years anyway.

You may surprise yourself. Personally I find working and having a regular schedule to be very stabilizing and healthy for me. Think of the possible good outcomes- you may enjoy it and be really good at it and meet new people and have more $ in your pocket each month.
Personally I would not disclose anything to your employer. Not to be cynical but stigma is real and you can't untell. Others may have different opinions on that. Anyhow good luck. In regards to CBT, if u can't afford therapy there are some decent workbooks out there you can do on your own. Just an idea. Take care.