Ah, lovely, it is nerve wracking. But perhaps, stay away from Google.
The surgeon who will be performing your op will have done it countless times before. They are experts in the anatamoy of your head, jaw and mouth. They do not want to break your jaw.
By all means, talk to them about it. But for now, try and focus on the here and now. Take some deep breaths. If you're having them out, they must be causing you some considerable bother and all of that bother will be gone. It has got to be worth it, right?
Also, it's very hard to be anxious if you sing. So maybe put some music on and sing along to calm your nerves. I hope that doesn't sound flippant, it's meant to be helpful.
It'll be over before you know it and, you won't have a clue what went on, because you'll be blissfully out of it.
Let us know how you get on.