You've probably heard the quote, "You cannot pour from an empty cup." It's true. In order to be of service to anyone, you must first do whatever it takes to get yourself in the right place.
For me, it's exercise, spending time with my dog, prayer & meditation, and slow mornings that fill me up. That's why I make it a point to do every single one of those things before I get to work.
Believe it or not, you're in charge of time. You can say no to that coffee meeting next week, you don't have to reply to that email, and you certainly don't have to watch tv tonight. Use your time to invest in yourself, then you'll be able to make a difference in the world.