Ms. Watson, your dog is not scared of the other dogs. It is just feeding off of your nervous state. I'm sure you are worried about everything because of your cardiac condition. Don't get too worked up about the other dogs. I have a large dog who is more mindful than children. He doesn't fight other dogs. As a matter of fact, he thinks all other dogs are just as playful as him which usually get him attacked about other dogs. It's how the dogs are trained and not their sizes that you have to worry about. Get to know your neighbors and you will get to know their dogs!!!