I am sorry it gets so frustrating!
I can relate. I've had long and severe episodes of depression for the past 40 years. Most of it has been treatment-resistant. It's complicated with medical/physical conditions. Much of the time I fail to see a light at the end of the very dark tunnel. It's been my experience the depression lets up when it's ready to do so. Little else influences the depression, except to make it worse.
Yes, my H had been anticipating a "fix" every time I saw my pdoc. It has taken him a long time to give up that idea.
I know, from experience, I eventually catch a bit of a break from the depression if I can just hold on. Some of my depressions have been at least 2 years long. It's finding a way to get through it that's so damned difficult.
I hope you can hold on and can believe there is a break ahead for you. My heart goes out to you.

WC