That sounds just like my Ginger's first trip to the vet. You can't do a whole lot at this point besides hold her collar to brace her and sit apart from the other dogs. One thing that I learned is to not comfort her or say Shh, it's ok because that reinforces her barking and pulling behaviors. Just try to be calm and hold her back. That being said, I have only been a dog owner for about 6 weeks now so others with more experience may chime in with something completely different