I'm not sure that I have anything to offer other than to tell you that I can understand that you feel overwhelmed. I am not a med professional but you go to work with the worries of your significant other and you come home with the burden of your work situation . . . .
Although your pdoc tells you to leave your job, I would probably not agree given the limited information that you have provided. You need some source of income, but you also need, I think, some guidance which, and forgive me here, I don't think your pdoc is providing. It is not as simple as to quit your job and therefore you will be happy. For me, it doesn't work that way . . . I would be more impressed with your pdoc if he or she started to figure out why you are unhappy at work. Is it everything else going on that makes the work environment unpleasant? I guess my question would be if you have considered getting a second opinion and perhaps a therapist who offers more than simplistic quit your job advice.
So, my first suggestion is to start to care for yourself and that may mean a second opinion === only you can decide. My second suggestion would be to find out what types of community supports exist to help you and to help your significant other who has a debilitating disability and make sure you access these resources to the fullest.
I know that this all seems overwhelming because it did to me . .. . I had to take such small steps to get back on track that sometimes it was frustrating and disappointing, but, for me, well, I guess I was just too stubborn to quit . . .
In your day, decide on one thing that you are going to do for you . . . it does not have to cost money . . . perhaps it is 15 minutes by yourself . . . but you have to be strong and not let others or other issues to postpone doing this one thing for yourself . . . work is probably generating an impending feeling of doom because you feel that is the scenario for your life but it does not have to be . . . it might be tough going, but truly if I can do it, anyone can do it . . . one of the worst things that I did in the beginning was simply accept that my life would be the way it was . . . .I did this for a very long time until I asked myself why this had to be and I could not answer that question . . .so, I made a choice . . .I won't lie to you . . .it was scary and you have the added issue of a significant other with issues whereas I had family illnesses of a different type . . . yep, it took time and I still work daily on managing my anxiety, but bit by bit things did improve . . . I will not be Bill Gates, but I am more or less in a place where I am happy with myself most of the time and i know that you can do it also . . . please, please, please . . .check in with us and never worry about whether you are posting to the "correct" forum . . .we have wonderful moderators who will help get your post to wherever you will get the best and most responses . . .take care, kc