I work at a dog daycare, so my dog is at this place 3/4's of the week so I'm sure that doesn't help his territorial issues. But today, he went after a pug and when I went to grab the pug to remove him from the situation, my 2 year old terrier mix bit me on the back and it drew blood. My heart is a little broken. I rescued him at 1 year old so he had no prior training. I take him to obedience classes every other Saturday. There are just these moments where he is no longer responsive to my voice & goes to crazy town. What do I do?