On two tracks south been there, done that, almost burnt out in the process. What worked for us was: take breaks.
Yes, breaks will take away from the precious boat prep time, but they will keep you and your family
mentally stable. Go for ice cream or some food to some park or waterfront and while at it do not talk or think about what still needs to be done
. Just enjoy the moment, ice cream, and your family. Talk about random things. Laugh.
Otherwise once you're on the cruise
you'll be recuperating for the first few days or weeks. Is that how you want to start "living your dream"? And if something goes wrong at that point (as all things do at some point) you might have a breakdown then. Avoid it, take breaks. The "lost" time will be worth it at the end.