Strange behavior

[ruger0771]

I've got a british lab that is a little over 2yrs old -- I took him to get him refreshed at the end of September and picked him up the first of November -- he has always performed perfect and never missed a bird when I sent him on a retreive-- I took him pheasant hunting 2 days after I picked him up from the trainer and drove fro about 9 hours -- when I arrived I noticed he was acting real timid -- during the week long hunting trip, he successfully retreived about 4-5 birds -- he acted as if he had no drive and would not eat -- has anyone had the same experience? I'm at a loss here..........