If you cease from existence from when you die then you can't really say your current existence right now is reality. You won't know from real or fake when you're dead.
I don't know what happens after I die. Maybe I don't cease from existence. I most certainly cease to be in this present reality, so what happens after I die doesn't matter.
But as far as I can tell for the meanwhile, I happen to exist. You might just be a stuffty figment of my imagination. But for all intents and purposes, I exist.
Even so you could have died from an instant and your entire reality is you reliving your last 7 minutes of brain function.
Those 7 minutes will be the longest time of your life.
I don't understand what you're saying, or what this is in relation to.