Christian people who really want to serve the Lord with willing, servant hearts sometimes neglect their own well-being. Jesus said, Love your neighbor as yourself. And thats not about being egocentric, but it implies that treating yourself right is a basis for treating others the same way.
You would take care of your best friend so that he can take care of others. You would try to understand him, and comfort him, and strengthen him all you could. You need to do the same thing to yourself, as well!
Christian writer Fredrick Beatner said, A bleeding heart is no help to anybody if it bleeds to death. That means not only taking care of yourself physically, but feeding yourself with divine nourishment from the Word, being merciful to yourself, accepting the bread of life from Jesus.