Since many of us live under the immortality delusion (death only happens to others), let me ruin your day once more and make you think again about death.
As Freud wrote "It is indeed impossible to imagine our own death; and whenever we attempt to do so we can perceive that we are in fact still present as spectators. Hence ... at bottom no one believes in his own death, or ... that in the unconscious every one of us is convinced of his own immortality "
(Sigmund Freud-Reflections on war and death (1915), Part II - Our Attitude Towards Death:
https://archive.org/details/reflectionsonwar35875gut )
Death is just a return to our natural state, our only real "home", where we already spent an eternity, before being born: nothingness.
It's life that is extraordinary, not death/nothingness, which is a normal state.
As Freud on the same quoted book said in great terms: "Everyone owes nature a death and must expect to pay the debt".
But the idea of being forced to be again nothing for another eternity, after experiencing this fabulous life, is something so catastrophic, that one can't avoid a well known, but still pathetic (because pointless), overwhelming sentiment of imminent and irreversible loss.
Imagine what future generations would think about us if it were found a mean to avoid aging and our usual mortal diseases and people normally lived thousands of years.
They probably would say that we were people who lived their life like shooting stars, burning intensively and illuminating everything around for just an instant.
People, who faced with the most certain looming destiny, kept going unremittingly.
Who were able to leave their pre-historic caves, imagine and create deliberately the most beautiful, intelligent and admirable things known on the Universe and even create means to leave this planet and conquer the stars despite the conscience of their pending fate.
There is something glorious on being able to do all of this despite the conscience that our life is little more than a blink of an eye between two eternities of nothingness.
It's like the last and pointless charge of a doomed battalion.
Probably, this destiny was in many cases precisely an incentive to do all these things. But that doesn't diminish its merit, on the contrary.
Death makes any meaningful* life gloriously tragic. Not only because all these admirable things done are pointless to avert this fate, but also because it interrupts the creative process. Think about all the things that Da Vinci, Mozart or Einstein could have done more.
Don't think for a second that this text has any depressive objective or expresses any negative perspective on life. What makes the human condition tragic is precisely the wonderful nature of life, despite death.
Rather this text is praise to all the atheists that face their destiny openly, keep doing meaningful things and dare to be happy.
Don't criticize life, because the problem isn't life, but death. Being our life a wonderful "miracle", because of its improbability (a part of us had literally the run of his life to live, the spermatozoid, and won over millions of his brothers), not enjoying it is much more absurd than our destiny it self.
Yes, time flues unrelentingly fast. And, yes, we have a short life. But it isn't that short on comparative life terms. Even if you, fellow reader, are still a teen, think about your first memories: probably, it looks like if it was another life, because of how long ago it seems.
* In the sense of a life with positive consequences to others: see the OP.