This might sound twisted, but something that helped me take more time to myself was when a guy who was "the only one who could answer certain questions" with something like 30 years of experience in our field dropped dead of a heart attack at home. We figured out what we needed to figure out soon enough and his position wasn't filled for a year because five or six of us took up the tasks he was in charge of... My point being, no one is irreplaceable. Disconnect when you're not at work.