What if your entire life is just a memory you're reliving in your final moments?

I hope not... but it can be an interesting thing to think about. If you haven't seen it, you should look up Waking Life, it's a... well, I call it a movie/documentary, cause there is a main character and he goes through this journey of self discovery, although it's mostly people talking about various things, like dreams, free will, existentialism, language and more.
Here's a clip that's related to what you're talking about.
[media=https://youtu.be/uJ0snEwBvqk]
Fun fact: The 2 characters in this scene are from The Before Trilogy of movies.