I've lost consciousness twice after being put into a blood choke. The experience of regaining consciousness is visceral. For those that haven't experienced it, it's very much like a turning on a computer.
Initially, your brain does not (or cannot) process input like vision, sound, touch, etc. Slowly, over about 30-60 seconds, you begin to see and hear but they don't make any sense. You've completely lost the context of who and where you are. Then you begin to recognize colors and shapes, sounds of voices, etc. Eventually, you see and hear everything but still haven't built a concept of the context. Lastly, your brain seems to begin making sense of all the inputs and you regain full conscious awareness.
If you think it's just like waking up from a dream or from a nap, you're wrong. It's a completely different experience, one that's so profound that I distinctly remember the entire episode even years later (and I have poor memory recall generally).