The practical difference between unconsciousness in the form of sleep and unconsciousness in the form of death is the life and the brain activity of the organism. It sounds to me as if you are confusing consciousness with our souls, which is not likely a justifiable juxtaposition. Our consciousness is our mental state (thoughts, feelings, awareness, etc.), whereby our soul is that part of us that connects with God (our spiritual being, so to speak). Thus my soul is distinguishable from my consciousness as the spiritual entity that is me separate from my mental capacity and functionality.

The "nothingness" and unconsciousness I experience during sleep is a completely distinct thing from the separation of soul from body at the demise of consciousness in death.

Where does the soul go (or what does it do) when a person is sleeping? Better yet, where does it go when a person is sleeping but not dreaming? Relatedly, where does it go when a person is rendered unconscious (through head trauma, medication, etc.)? In other words, what's the practical difference between being asleep and not dreaming vs. being dead and not existing in any conscious form? I ask because personally I don't see a meaningful difference between being unconscious and dead (aside from maintenance of bodily functions) when it comes to consciousness. This relates to the afterlife in that what if the experience of unconsciousness—i.e. no sensation, no awareness, essentially nothing at all—is exactly what happens when we die? Do Christians have an explanation for how we can briefly experience "nothingness" through dreamless sleep / genuine unconsciousness if we have a soul that exists as a permanent form of awareness? What's the fundamental difference between a person who sleeps without dreaming and the atheistic concept of the annihilation of the self upon death?