A good quote on this:

It is true that the changes brought about by human action are but trifling when compared with the effects of the operation of the great cosmic forces. From the point of view of eternity and the infinite universe man is an infinitesimal speck. But for man human action and its vicissitudes are the real thing. Action is the essence of his nature and existence, his means of preserving his life and raising himself above the level of animals and plants. However perishable and evanescent all human efforts may be, for man and for human science they are of primary importance.

In other words, even though it's true that every war, every destroyed relationship, every wonderful interaction, and everything else that's ever occurred in history happened on the pale blue dot, most likely quite ephemeral in its existence by contrast to the rest of the universe, this doesn't change about the fact that we as humans are programmed to care about certain things--things that do exist at this time, however transient they would be from a universe perspective--and this is the source of all enjoyment and suffering. The goal is to be on the 'enjoyment' side of it, of course.

Nihilism is just a confusion, a failure to take seriously the maxim 'it all comes back to normalcy'.