Have you not proven over and over that you are alive right here, right now? Every moment of joy and pain reminds you of your existence in physical form, safely anchored to earth. What is the gain of spending so much time in your head, anticipating, maybe dreading, what is to come and when? Acknowledge and learn from the past and engage in the present. Observe and feel. Live your life instead of spending your time on ghosts stealing their way into your mind. They don’t exist. You do.