I agree too that the loneliness is torture especially when the depression starts. I know I have to aggressively fight the isolation issue as I naturally am a loner. I've come to the conclusion that the only ones who can connect with me over these issues are fellow sufferers of depression. The average person is just too intimidated somehow. You can try to reconnect with old friends even superficially and see what happens. Force the interaction to see their reaction. Maybe they are wondering what happened to you.

If you feel lost now, what guided you and kept you going before? I try to grasp anything that brought me simple pleasure. When I feel as bad as you describe, I focus not on the day but on the moment--an hour at a time. That's what I have to do. The future becomes worries that I can't figure out.

I hope you are feeling better and know there are plenty who feel as you.