HI! You know that comment you responded to I wrote? In case you didn't know, the story I was referring to is called LopE.
Intolerance to a strange energy source that engulfed the earth, mass disappearance of all animals with a sufficiently large brain, the basics of loneliness and surviving in a world where the only other life forms around are plants and microbial, meeting others by unlikely chance who had the same misfortune of losing everybody they ever knew, everybody eventually coming back be it in minutes or centuries.