I completely understand your nerves about tomorrow; I was very nervous before my LLETZ as well and I don't think anyone goes to it without nerves - looking back, I think it was the element of the unknown about how it was going to feel that made me nervous. However, it's really very do-able. To be honest, because of the local anaesthetic, you hardly feel anything and if my consultant hadn't told me, I wouldn't have known the exact moment at which he was removing my transformation zone because it didn't feel drastically 'different' from everything else he was doing while he was down there!
You can ask to watch what they're doing on a large TV screen (located at an angle which is convenient for you!), which I did and it helped simply because I found it interesting and became a bit engrossed in watching what was happening! That's not for everyone though - some people, completely understandably, would rather not see it - but I'm one of those people who wants to see and know everything!
I think you're right that it is preferable to have someone with you - perhaps you could try ringing a friend you haven't tried this evening, just to see - but at the same time, it is completely do-able on your own and the nurses who are there with you are usually so kind, so I am sure someone will hold your hand and reassure you.
This time tomorrow it will all be over and done with and best of all, the overwhelming likelihood is that will deal with it and that will be that! Yay!
Good luck. Let us know how you get on.
Love, Annabel. x