It served me well when I’ve had similar concerns to take a week (or as close to a week as I can manage) and take very good care of myself.
I found when I was operating on eight hours of sleep, adequate exercise, and also doing things like yoga or meditation to manage my stress and anxiety, I felt worlds better physically and was mentally sharper. This sounds obvious, but when you are in the thick of everyday life, these are the first things to go.