Start by doing things that involve being outside. I find that just being outside seems to establish a greater attachment to the rest of the world, and some motivation to continue to be in it, and want to make it better.

Better if there's also something you can do with other people. I play tennis and I do inline skating. It gets me out with people, and not always people I would choose, which provides some amount of grounding / self-checking.

Start a little project, remind yourself of what you can do, and what you're good at doing, and what you enjoy doing.

If you have to sit and watch TV, I've found Halt and Catch Fire to be somewhat motivational to "do something" and find the dark corners that can be probed and pushed (and HCF likely fits well into the interests of HN folks).