By reminding myself that unless some space rock suddenly hits us or the sun decides to explode super early, we're fine. And if you look at our history as a species, we'll continue to be fine. We've endured far worse things than this before and we'll do it again and again. We're good at that. Stupidly good. Whatever rough spots we're facing now is going to pass. It's always passed. Can't be bad all the time, after all. As for global warming causing a potential extinction event? It...more than likely won't happen in our life time, so, worry, but don't, like, believe it'll happen tomorrow or that we're already actually facing The Great Dying 2.0. We're maybe at the crossroads, but not there yet.
Other than that? I do as a few have already mentioned here and try and make the world just a slightly better place. Helping others in my community out, being kind and considerate to the people around me, trying to not get frustrated at drivers out on the road (this is tough NGL), that kinda thing.