Other have said it, but you should probably take some time off. And by that I mean, actually take time off without checking email or slack, or quickly helping put out a fire. I worked for a high growth start-up and I'd always end up checking in on something or answering some questions during my time off and it just negated any benefit from taking the time off.

Also, you mention not having motivation to work on personal tech projects, and I can relate to that. I don't have a good answer except that you don't have to do any of those projects now, and it's probably better for you to find a non-tech related hobby like cooking. You'll use a different part of your brain, while also creating something and solving the occasional problem.

Also, and I say this to most people who are struggling with work, but therapy is a great outlet to help you explore the pressures of work and strategies to deal with them. When I worked at a start-up, half the reason I was in therapy was to have a neutral outlet for venting my work frustrations that wasn't my significant other. It's not for everyone, but I highly recommend giving it a shot, especially if you have insurance since there's no real downsize except for the hour or so the session takes (especially now that a lot of therapists are doing virtual visits).