I last left this morning for work. The last I left for my own enjoyment was last weekend for the Pride parade. (State of GA in the USA celebrates in October for some reason.)
(I tried to spoiler this bottom part since you didn’t ask for advice, but I guess I don’t know how. Sorry.)
I suffer from chronic depression, so I might know something of what you’re going through. Hang in there, friend. It gets better, eventually.
Also, I know this probably sounds ridiculous (it does to me when I remind myself of it while depressed, especially since I’m also autistic and antisocial) but the safety of home makes depression worse for me. It’s the last thing that I want to do while depressed, but it really does help tremendously to get out and do something. Anything. Go to the grocery store and buy a ramen or whatever, it doesn’t matter. Go through the human line to checkout so that you have to interact with a person in some capacity. It’s silly, but it does help me a tiny bit.
The next day, try to do it again, it helps a tiny bit again. Eventually all the tiny little bits add up, maybe, but even if they don’t then at least it’s a tiny bit better all along.
Calibre will work for this, but it almost certainly won’t give a good result. That’s not Calibre’s fault; Adobe InDesign produces exactly the same horrible output from a PDF. It’s just a reality that PDF does not lend itself gracefully to being converted easily to a well behaved EPUB.
Unless you are converting something extremely simple with no inline images or interesting text layout, getting a nice EPUB will almost definitely be a tedious process of fiddling directly with the HTML and CSS with something like Sigil (or Calibre, but it’s not as nice).