We have a 10 week old lab mix puppy. We had him for 3 weeks and then we went on Vacation. He stayed with a friend that has a 11 week old lab mix and 2 year old lab. He loved it there. He played constantly. Now we are home. He now has diarrhea, and seems like he is looking for his friends. How long will he seem sad and lost? Do you think he forgot who we were?