I recently adopted a jug about 2 weeks ago. He has serious separation anxiety. It is a task to leave our house! He barks and jumps at the door to stop us. Today he nipped my fiancee's foot when we left. I know he has been through a lot. He was found by the animal control in May. I've heard it takes adopted dogs 6 weeks to adjust, but I want to work on this ASAP! What can we do to decrease his separation anxiety?