I worry more about sooner than later, too.
Hell, the core of the planet could vent enough gas one day to poison the atmosphere, the sun could go into a phase that destroys all life, or a black hole could swallow us up.
I had a fair day today, hope to had a better one tomorrow, but if it all ends tonight I will go gracefully. My only regret being that I did not learn how to be at peace with myself sooner.
I grew up fearing atomic bombs during the cold war. After that, nothing much bugs me anymore.