So I have a 2 year old rat terrier/American Eskimo mix named Winnie, that I got at two months old. I took Winnie to training classes, socialized her and every thing. After she was one year old I started taking her to the dog park once or twice a week. All was good and well tell both her and I got attacked by a dog. She was playing fetch and a dog just ran up to her and started attacking her, she was a very submissive dog so she just rolled on her back and cried. So I scream for someone to help and I picked her up and held her above my head. This dog then proceeded to attack me while trying to get to her. This dog dug it's nails into my side, bit my side trying to climb up to her her. My shirt was ripped and I had blood running down my side. This is when Winnie snapped, it was like something clicked in her head. She saw me getting hurt so she needed to protect me. She jumped out of my arms and went full force at the dog because still no one was helping me. Finally some guy came and helped me pull them apart. Now everytime she sees another dog comes near us she growls. If she sees them from a distance she does not care. I really need help on this because it's so sad to see another dog come near us and she refuses to accept them. Any advice would help.