You are part of this random person's subconscious, yet they have developed a backstory to every person they see in their entire life. The time this person dies is the time their world ends, and because you are only a part of their world this is the time you die as well. You are only an unpaid extra in somebody's dream while they are asleep/in a coma/etc.
you aren't real
your family isn't real
space isn't real
this website isn't real
you could be part of the mind of somebody living galaxies away (their galaxy possibly seeming nonexistent to you because you are nothing but a person casually sipping a drink in the background of one cafe the person in question went to one morning on one vacation.)
how do you feel, not existing in what is actually the real world?