I think you're burned out and the personal stuff in your life is taking more of a toll than you think. I think you need to take some time off work, i.e. "mental health/self-care" days. Take at least one day off to just do nothing and chill out. You can use the other days to take care of your personal stuff. Take as much time as you need.

Also, if you're gonna quit your job, this is probably one of the safest times to do it.