Generally I've chalked these feelings up to a certain type of existential dread. Described in this article[1] fairly well.

Kind of reminds you of the total perspective vortex from the hitch hikers guide to the galaxy. Truly, on a universal scale even the most important and impacting human on an earth scale does about as much as a neutrino interacting with us.

[1] https://medium.com/s/story/are-you-suffering-from-existentia...