Everyone is insignificant to someone. Irrelevant, likewise.
There will always be someone - scratchthat, there will always be people - who don't care, about your life, your well-being, your existence.
Who don't give a ****.
But there will also always be some who does, one who truly cares. Maybe they're your family. Perhaps they're your friends. Or you mightn't have ever met them.
Imagine all the possibilities, dream out all the outcomes. Maybe there's no one there now, but nothing lasts forever. Maybe you'll encounter someone new. Or maybe someone you know does care, and you just haven't noticed yet.
Because if there isn't - if there's no one out there now, and there never ever will be - Then there's no hope either, is there? and if we don't have hope - that someone, somewhere, thinks we have some kind of worth - Then what is there left to have?