Nighty Night time...

We have an 11 (almost 12) week old Cocker Spaniel puppy that we adopted about a week ago. He's a great puppy and we love him already.

Here's my problem. During the day I'm trying to gradually crate train him and he does.......well, ok, but at night he HAS to be in the crate to avoid the complete and total destruction of my house and everything in it. When he is settled in his crate at night he does great all night with no accidents and no noise until morning. HOWEVER, when he first goes in he barks and whines and jumps around for about 20 minutes. I don't know what to do. Should I comfort him? Should I leave him alone and let him "cry it out"? Will he get used to it and eventually go in without a fuss? I know letting him out is a no-no because then he'll think all that barking and whining works, but I feel so bad for him and I'm afraid he's being somehow mentally damaged by being locked up. Am I just nuts, or is this sorta normal??

Thanks in advance for any help.