Im 17 and ive had 49 operations in my life now, first one being when i was 2 days old, so i know exactly what happens man
You can choose to have the local anesetic (cant spell it but its the stuff that puts you to sleep lol) either in your arm through a canular (needle that stays in your arm with a little tap thing on it, then they inject it from a syringe into the little tap so u dont have another needle going into your arm) Thats the most direct way, and they say by the time you count to 10 your gone, the record is usually about 6, i always try and beat it for fun before i go out haha. If not they can usually give u it through a gas mask. It smells kinda bad but its another way if you prefer that.
You dont dream or feel nothing while you sleep, you wake in a different room which is recovery. Everything is usually blurry for a bit and u just slurr your words coz your drowsy. After a while you can focus and **** but u usually go back to sleep, the time depending on how much stuff they gave u, depends how long the operation took.
I remember on my biggest operation, going down at saturday afternoon, operation took 12 hours, and i woke up next to my mum and said what time is it, and she said "its wednesday night" i was like WOW, and i missed out on the whole summer holidays at school, was in hospital for about 7 weeks, 3 month recovery after that. In total ive missed over a year of school it was worked out from operations lol.
But dont worry you will be fine and nothing like that, im just ****ed up!