When working on the boat in marina? Eat and sleep normally. Drink a lot of water. Do not to many projects to prevent mistakes. Mistakes means damage. Damage means shock for nerves. And nerves are not infinitive. I had a brake down this season. I bursted in tears. Next day I realized what was going on.
When sailing. It is mostly the same. Try not to be impulsive to not make mistakes. Then you should be fine. But be careful not to get to tired. You can then lay on the bed and say: “Who cares!! All may go to hell.” Or you can find yourself on reefs after fell asleep on legs.