For approximately 14 billion years, give or take, you did not exist. You don't remember what things were like before you were born. Time didn't seem to pass because, for you, it actually didn't...you could potentially have even been in a state of nonexistence for orders of magnitude longer than our current estimation of the age of our universe, and yet more still, and so on and so on, down through the entangled lattices of just as many billions of other unknown variables. However, regardless of all of this, your "experience of nonexistence" would remain the exact same: one day you were just here. And, eventually, you will return to this same state of nonexistence. But you've been there before. There is nothing to fear.
The fact that we are here at all proves that incredible events such as sentient life are more than just possible; they will definitely occur given enough time and the proper conditions. No other fact of reality can be as true as this because it is self-evident and precedes all other observable elements by virtue of observation itself. So who is to say that many other fulfilling and satisfying events won't occur in a way that "you" will some day experience at some point after you return to nonexistence? It's already happened to you at least once that you know of because you are reading this.
The possibilities are nearly endless. Perhaps some of the more human ideas like religion and other forms of afterlife could all be similar to experiences that we may actually have sooner or later. New universes or alternate frameworks of reality itself may some day form or even already exist out there somewhere - we know ours certainly does - each one with their own set of probabilities and variables and conditions. As well as countless other things which we have no way of imagining.