Hi toffeecushion
I'm really sorry you're worried, most women are apprehensive about this sort of stuff! If you've had one done before though and found it ok, then it probably means all will be fine for you this time, especially as they are giving you a local anaesthetic.
To be honest every woman could probably tell you a different tale re this procedure. I've read on here that some women didn't even feel it and can't understand why some women make a fuss, others find it more difficult. I had one done without anaesthetic but they couldn't get through my cervix due to heavy scarring. When that was obvious they stopped trying and then I had to return and have it done with a GA. A close friend had hers done a couple of days before me and she was in and out in 15 mins. We are all totally different.
Whilst the whole shebang of having our lady bits prodded and exposed is something we'd all like to avoid, think how reassured you'll be when it's done and dusted and you know all is well!
Good luck, I hope all goes well for you and don't forget, if at any time you can't cope with it, tell them to stop: they will!