That sounds like burnout, and possibly depression. It does get better. I went through a very bad bout of it in 2010 (my last 6 months at the day job prior to quitting was a 90+ hour a week death march) and lost essentially six months after quitting. (I did an honest week of work over the entire interval, and only clearly remember two days of it.) I have had a struggle or two with depression since then but late 2010 through now were the best years of my life, by quite a lot.

I'd encourage you to see a professional, and re-connect with the things you like in the world that aren't working. Also, it was a big surprise to me, but the guys saying Exercise And Diet Matter were actually right all those years. I know your body is saying "Go to the gym? Oh, eff that, there's a perfectly good bed right here." but if you can force yourself to do it every day, even for 15 or 20 minutes to start, it does a world of good.