When I was depressed I would bail on activities all the time. I knew I'd have fun if I went, at least in theory, but I just - had no interest in making myself go. Unfortunately, after a while, this active inaction can become a habit. I had to learn to start making myself go to things that, on a removed level, I knew I'd enjoy and would help me connect with people. I guess it was probably also a fear of interaction? I don't know. Anyway, I know that feel (kind of - it's hard to tie my present day back to that self). I would just say, start practicing making yourself go/do things. Don't try for 100% success or attendance, and allow yourself to bounce if you don't like a thing once you show up there. But I think sometimes we can build habits out of depression and then, even if the depression starts to resolve, continue those habits because that's what they are, unless we work to break them.
I'm going out and doing a lot right now, sometimes it's hard to make the call because, to use tonight as an example: planning on going to a concert by myself and hoping to try and meet people at it. I don't think that's a very easy thing for a lot of people, regardless of mental state.