What advice can you offer me?

I bought a male shih-tzu and he is always crying . It will be 3 weeks at the end of this week that I bought him. He seems as if he just wont adjust . Why? It's very fustrating everything I have gone and done for him has not helped ease him up. I have a 1 yr old shih-tzu and I never had this much problems. My 1 yr old settled in with us with in 3 days. I know that when I got my 1 yr old he was 10 weeks old and my new one he was only 7 weeks old. Ya BIG DIFFERENCE! But I figure he'd adjust by now. he'll cry all day and night. I think he's hungry but he eats like tomarrow! He eats more then my older one. I make it comfortable in he's crate blanket/ stuff animal and all.. I only crate him in the night for he's safety. Anyone has any advice. I was thinking about putting him back on milk. I 'm planning on calling the vet in the morning cause this is crazy....What advice can you offer me?
3 weeks should be enough time for a new puppy to adjust.


I would definitly take him to a vet..there may be some sort of medical issue.What advice can you offer me?
The vet is a good idea. Or, teach him something to occupie him. Teach him how to swim. Or, take him to the park and let him run around. The leash isn't a good idea but he might run away. Let him loose in a big yard then. When he is happy, he'll get occustomed to not crying and things.