The uncertainty regarding the cause of your existence does not have to have any negative effect on your sense of meaning and purpose during your lifetime.
You decide what meaning the events in your life have to you.
https://yourmeaninginlife.com/blog/you-can-find-meaning-in-whatever-happens-to-you
Asking where you see yourself in five years is a good exercise to determine both where you're going and what you want to be doing today to reach your desired future state.
https://yourmeaninginlife.com/blog/where-do-you-see-yourself-in-five-years