I'm the same, though my fear is about the local anaesthetic not working. I'm not scared of injections in the mouth, but now, having my blood taken, that's another thing!
I think the fear of injections is indeed quite rational, because they cause pain, and pain is something to fear.
jipsquithesq, I'm phobic, utterly, about dogs, especially the bull terrier/Rottweiler varieties, and the amount of times people say 'Oh, he won't bite' and I feel like saying, 'How do you bl**dy know, you idiot, he's an animal and has jaws that can kill.'