Therapy helps and you may need medication. Depression is no different than any other medical illness that requires daily medication to control the symptoms. I would see a psychiatrist so the two of you can determine what course of treatment is best for you. It's tough enough to deal with a health issue that nobody can resolve, you shouldn't have to deal with the depression on your own. There's help for you, and no reason to continue feeling like this. I wish you all the best and do take care.
I can understand your pain .. the best way of getting rid of this depression would really be by eliminating the disease that you have.. otherwise you will have to some how learn to live with it and the depression may heal by the passage of time.