Be selfishly selfless
The idea of being selfless is great. Constantly putting others ahead of you seems like an admirable way to live. It is, perhaps, but it won't work. In order to serve others, you need to take care of yourself first.
If you've been on a plane, you know the safety drill, and a big thing they point out is if oxygen masks drop down you need to secure yours before you help others. You might want to rush to help others first, but when you pass out on the floor you're of no value to anyone else.
In his book "Life's Amazing Secrets", Gaur Gopal Das calls this being "selfishly selfless". As he has said on Twitter:
Take care of others around you, for sure, but don't forget to take care of yourself too.