Sounds like a Random Thought, viable for posting in Random Thought Thread. Feel free to redirect yourself over there, as well as replying to my takes on this matter.
I've read this somewhere on the net. Like, people passes out if they're not getting enough oxygen. What if oxygen is making us hallucinate about this world, and the actual world we lived in was just a void of darkness that we were able to get a glimpse of when we passes out.
Again redirect yourself to Random Thought Thread (RTT) for replies, I'll see you there.