Almost drew today. (First time) [aggressive dog]

Let me start this with a confession. I have always felt more like one of the "wish a mutherfucker would" types. Maybe it was just my age/testosterone, I dunno. After this situation I really feel different. I know I am just like everyone else who will try to do everything to leave the situation with no injuries. If anything I need to train away my "freeze up" tendency.StoryI was on a short mid day fly fishing trip with my wife at a local "park" that is basically woods and trails with a creek.We came down a path towards the creek, and heard someone whistling and yelling about 100' away. We started to leave, Then a pitbull came charging out of the bushes towards us. I don't sterotype breeds, and I thouroughly understand dog behavior(been around them my entire life). I have been in similar situations with large dogs that were just defensive barking to alert their owner.This dog was silently rushing our turned backs, low growl, and only slowed when challenged, and only stopped when I used my 7wt. Fly rod as a physical barrier. At this point I had my shirt cleared, hand on my gun (p2000sk 9mm) and wife behind me, owners no where in sight, and the dog held back by my 9 foot fly rod. He was about 7' away kinda wedged under it because it got stuck on a rock.I calmy but firmly/loudly said " I don't want to be your friend, go home" We both kinda backed off slowly.I know he could have gotten too me before I drew, 7' is an instant. I also know pepper spray may have been ideal but I would have had to drop the rod(which means bending over to pick it uo before retreat) , or draw spray rather than gun, and that seems stupid?I was scared to draw because I didn't know if the owners would see me and start a bunch of bullshit, and I didn't know if that would trigger the dog. I also didn't react in time to get the gun out before he stopped, because I am so optimistic about dogs being friendly.Advice? What should I have done different? Will a subcompact 9mm even kill a dog like that if I shoot it in the head? via /r/CCW http://ift.tt/28PxaL0