I understand your history a little better now. I also used to think that being in the social work or psychiatry or similar fields may increase depression....but I am really not as convinced anymore. These certainly can be challenging fields for those with some depression...but the good news is that you can use your professional skills & experience to heal yourself.
One thing which comes to mind is the possibility of hormone therapy. It clearly has its own risks, but it's worth discussing with your GP. I have seen many women get better emotionally with hormone pills...but I have also seen some get worse. The only way to know is to try it if your GP thinks it would be safe for you.
I'm not sure which treatment you don't want...CBT or medication. You have absolutely nothing to lose by trying CBT. It is a powerful & effective treatment. And in most studies on moderate to severe depression, the best results tend to occur by combining both treatments together. I'm not saying you should go on medication...but I would stay open minded to the idea if your depression continues.
Last, make sure you treat yourself holistically. I have seen many patients get better with meds...but then they ignore trying to balance their lives with: nutrition, exercise, stress management, psychotherapy, and relaxation therapy.
The last 2 treatments I mentioned are proven by sophisticated studies using brain scans (CT, MRI, EEG, pet scans) to improve brain function.
Also, by formal relaxation therapy I mean yoga, meditation, or similar methods. Having relaxing hobbies is also important, but not quite the same as formal relaxation therapy.
The job decisions sounds difficult & complicated. I would definitely discuss it with your union...and also with the CBT therapist (along with any trusted loves one in your life). Take everybody's opinion with a certain grain of salt, and in the end follow what your mind & heart tell you.
Is there anything else I can help with?