You're certianly not alone. I have a terrible gag reflex as well. Needless to say, all my appointments are first thing in the morning and I don't eat before them.
I had the same hygenist since I was 6 years old. It was nice because she new exactly what made me gag. Unfortunetly, she has now moved and I need to find a new one. I've been putting it off but I need to go before I wind up like our poor root canal friend.