Hi kmb1 - welcome to the forum!
It's remarkable how selfless so many depressed people are, and how those very same people think they are selfish! It often seems to me that only good people become depressed - I mean people who really do try to "be good". And when they find that their efforts to be good are not appreciated or supported, it just takes all the meaning out of life - "totally let down by life in general", as you put it.
It may be time for a rethink about what you really want from life. But before you can do that, you need to pull out of some of the effects of depression. Have you looked at the
Depression Learning Path yet? Have a good read of that, and come back and tell us what you think!
Kathleen