I understand your worries. I had to have a couple of GA's a few years ago and I was petrified even though I'd had two before - the difference was I had children this time.
After the first one I remember thinking that was fine, I won't be scared again. I had another one about two weeks later and I wasn't scared!
But..now it's been a few years I think I'd be scared again.
No doubt you'll be on here soon telling us how you wish you hadn't worried