There's the life means nothing position, which is reasonable, but I prefer the view that we constantly inhabit the world we create, in a material sense.
Whether this life is it or one of many forms existence takes, the one constant we can be sure of in this life is that it's gonna suck if we run out of the things we need.
Most people's anxiety is driven - Buddhists get this totally right - by attachment to things that aren't really needs, just obsessions. But living in the real world means being one step away from misery at all times.
So the key to happiness? Eradicating as much danger of misery as possible. Which requires acting on the world to mitigate it wherever it is found. Through action, the world is changed, and if it is done thoughtfully, it might even be changed so it sucks less for everybody.
Call it my welp we're stuck in this pit so may as well build a settlement theory of existence. Could very well be that life is eternal, and this is what we're always doing.
This view has the advantage of being proven by science - after all, where people cooperate in peace life is objectively better compared to one where they slaughter each other over water, no?
So whatever you've gotta do with your rock, cool, but if you can please join others in throwing said rock at the jackholes who are hoarding all the wealth and making the world suck :)