There's no feeling. It just is. Almost all people who har been pronounced clinically dead but resesitatrd experience some sort of nonphysical perception. There are many books and documentaries on the subject. And I think we can agree that if the experiencer has seen or experienced a Astral or causal plane. And knows that the "i am" of the self still exsists in a non-physical realm than of course conscienceness goes on. But perhaps this experience of being without a physical body is so unnatural to how we are wired from birth to think that it takes more than faith. And logic will always fail to explain because it is unexplainable. Logic tells us yes, here we are, this is it. Get it while the gettin is good. This takes awayresponsibility. Our souls are timeless. Not eternal because eternity is defined as all time. But timeless. As in exsists before during and after time was set on forward trajectory. This is strange to think bout but here's a good question that deserves thought. Time is only relative to space. Outside of space, and all the laws of the natural universe, the progression does not exsists. Near a black hole time is sped up. Gravity Is intertwined with the illusion of time. Just as gravity is an illusion of the physical arena itself.
But If paradigms are shattered by a mystical, transcendent or non local perceptions than you can't go back.
Ok so I'll answer your questions now.
First. You stated. Death is loss of consciences, just like sleep. That almost proves my point. Of course we lose the ability to consciencly Perceive this world. Bit as in death just as sleep there are experiences and events which are non local. Dreams. Wow. What a profound thing. To be an experiencer in a strange and limitless world of the dream planes. And anyone who lucid dreams will attest to knowing who they are, that they are in fact sleeping but stillexperiencing. being born into human form is basically the same. We are dreaming. Lost. And only once one realizes this fact can they be liberated from birth death pain and suffering.
How can I be sure I wasn't imagining. Ok you got me. I can't prove to anyone that I was anywhere other than here. All I can do is tell you about it. Perhaps spark an interest in visiting yourself. But you and all soils have been there. Each time when our soil exits this stage and is bathed in pure bliss and extacy you will remember. And also know as to why we must forget our true home in order to have a human experience. Every aspect of our journey will be laid out before us an each second will have had a purpose. Each person we meet, every twist and turn out lives take, will be like a orchestras of unimaginal design and detail. All leading (hopefully) to a point of god realization. Or the realization that we are all god conscienceness In human form. Lost just trying to get back home.
Strictly my opinion and is neither serious nor important
Space is eternity; if you can become directly aware of the space in the Present Moment then you will see eternity, there is no time, Eternity, the real living universe is Timeless. Time is the measurement of relative motion, it is a concept in the mind that has no real existence out there, in the real living universe. If you can raise your awareness and become completely Present I'm sure you will understand what I mean by Paradise. Come into your kingdom, lay your mortal soul to rest, let it be conquered by the light of your awareness, stop your thinking and just be.
You are God conscious in human form, but you don't have to die to realize it you can awaken to the truth right now. The mortal soul (ego, heart and mind, False self) is lost, but the immortal spirit(awareness, the Silent Witness, You, True Self) is forever found in the Kingdom of heaven, paradise. You have to get back to the garden if you want to find peace, and don't trust that clever little snake inside your mind(the ego, the Thinker) because it will never lead you to where you want to be, it will trap you in the illusion of time and you will remain lost, completely blind to ultimate reality, completely blind to this peaceful paradise.
Yes consciousness is indestructible; You are indestructible, eternal, timeless; you have always been and will always be; you are one with the whole of space, one with eternity, one with God; you are the container of all space time; you are what allows the universe to exist; you are the alpha the omega and the living One. Come into your kingdom, dine with me in Paradise.
Can't you see that I am trying to give you the entire world.
"Everything that I have told you is not for me but for you yourself" Muhammad
I don't have a need to convince you of anything I'm simply trying to invite as many people home as possible. It's ok if they refuse; nothing is important.