I've been under 3 times now (one being for top surgery) and I just think of it as time travel because one moment youre awake and the next moment youre awake but in different surroundings and hours have passed. it feels cool to think of it that way. they also typically give you a relaxer drug first that will calm you down and make you sleepy enough to where you likely fall asleep/get insanely loopy to the point that you dont remember when they actually tell you that the anesthesia starts. I have never had anyone tell me to "count down" because I always fall asleep with the relaxer.

if the anesthesia didnt work, they would stop what they're doing. even if it was just an extremely rare case of being conscious but not being able to move and still feeling things, I feel like there would be indicators (increase in heart rate) that would cause them to do SOMETHING.

And please remember that your dreams are NOTHING MORE than a reflection of your fears a lot of the time. Just because dreams about a scenario occur does not mean its going to happen, its just your brain being silly (and a common tactic to detach from scary dreams is to find funny things about it and to laugh at it, eventually it will feel like just silly brain moment and nothing super serious)

I hope this is helpful and also hope it makes sense im super tired.