I wrote what follows to help you. You apparently are willing to knock yourself out for your job despite what this effort of yours has done to you. I am hoping that your boss is able to see it this way. However, even if this is the case, he has a boss that he has to answer to. They may not be as amenable to such an arrangement for accommadations, particularly in your case. After all, you have taken off months at a time from work.

Now I understand that you needed to take time off for your mental health. I understand the necessity that this was to you. I probably would of done the same thing if I was in your situation. However, when does this get to the point where you become a liability to your company? Would you blame them for thinking this way? I hope this new arrangement works out for you. I am happy they are trying to work this out with you. If it does not work out, I think it is in both of your interests, you and your employer, for you to find a job that you can manage much better that is in a relatively stress free environment. Then you would be able to be there and be productive while you are there. This type of situation would then work for both you and your new employer. You may not make as much money, but you need to understand it has to work for both you and your employer. For that matter, I cannot see me living in such a work situation of high stress and anxiety just to survive. Such a new job would meet these requirements. You would no longer have to feel bad about your inability to mentally function on the job. You may be able to go back to your chosen profession at a later time.

I feel for your situation. I would never want to find myself in the situation that you are finding yourself in now. I hope this works out for you. Take care.