I went through a long period over the last 18 months that I have described as falling down a series of stairs. You hit the landing and think you are on the floor. Then you roll off the landing and fall down another flight of stairs. This continues until you are pretty much bonkers.

For me, I found that two things were helpful (meds have not been very helpful). Allow things to run their course - you don't have all that much control over it, especially if you have endogenous depression rather than situational depression. Second, lower your expectations of yourself until they align with what you are capable of. Only then can you begin to make progress in little baby steps. And you should congratulate yourself over those baby steps even though they would seem ludicrous from the standpoint of your former healthy self. That was you before - what you have to deal with is you now.

I think you are angry because you are frustrated. Just let those waves pass and move on. Acting out of anger is almost certain to be counterproductive and to set you back further.

I think of depression as standing in a hole a little taller than I am. As I turn around, all I can see is dirt. Nothing positive. But that is today. Tomorrow may be different, and it is often enough.

My favorite sig line, which is so bang on it's scary:

"Never deny in the dark what you know to be true in the light." - lightanddark

That's it in a nutshell. You might not see it, but you can maintain your faith that it is still there.

All the best ...