You must matter to yourself

The drowner can't help the drowning

If you accept the premise that you're irrelevant, you'll cut yourself down to size and your experience will conform to and confirm expectations.

You have to matter to yourself. Not in an egotistical way - in a compassionate way.

You can't truly love anyone if you don't love yourself. You obviously can't demonstrate skillful living to those you care about if you don't practice it yourself.

To the extent you can square away your own existential situation and not labor under a needy, energy-hogging psychology, you'll be better positioned to put your undivided resources into serving others.