So I started taking Leo, my 14 week GSD, to the dog park last week and he would not play with the other dogs there. I took him to the smaller dog park because he wasn't big enough to go to the big dog park yet making him one of the biggest dog there. Whenever a dog comes up to him, he would put his ears back, tuck his tail between his legs and lick the other dog's face. Is this normal? At home he is very energetic and playful. How can I help him gain some more confidence?