Anyone would be depressed and stressed out in your position. I don't see how you have coped so well. The fact that in spite of your depression you are able to be so proactive in your husbands care is truly admirable. You need to take care of yourself. You need to get medical support for your depression. It's probably too much for you to deal with all alone. Since you have sought help so much time has passed and there have been so many new treatments discovered. There is hope for you.
IMO you need to get a little time away from everything. Take a walk in a pretty park, feed the ducks or the pigeons, watch the dogs play or the children play. Go to the mall and window shop. Treat yourself to a lunch out. These things aren't expensive but may get you a few minutes of distraction from your stress.
And of course post here freely. We are here to listen. You might find support in the other forums on this site. There are so many.
I hope things