Are you able to discuss your problems openly with your friends and family, whether it be about your employees, your investors, or your customers? If you are open about your problems, basically you are vulnerable at all points.
This will help you stay sane because when you show your vulnerabilities, other people will also talk about their problems and you will realize that everybody is actually in the same boat as you, with some degree of difference of course. That is the simple way of looking at things.