Surgery at the orthodontist???? Need advice please!?

Next month I am supposed to get a gingevectomy AND a fiberotomy all in the same appointment. They say it will take about an hour and fifteen minutes (which seems super long to me). I am supposed to have a consultation next Monday and I do NOT want to be conscious for this whole thing. I get really nervous whenever I am at the ortho's office and I tend to freak out/hyperventilate/etc. They told me that the normal procedure is to just give you some shots in the gums and numb you up but even when I get a cavity drilled I can still feel it. So which is better :the nitro or being put to sleep? I just don't want to be able to feel it, I don't want to be awake! Just thinking me about it freaks me out. So which is better? Any advice? Has anyone had either of these procedures done? Did it take long to heal? How did you feel afterward? Thanks :)