med reaction?

Question
We have a medium haired cat of no specific breed. He is no more than 4 years old. He had his shots five days ago, FELV, and he is not himself today.

I would never characterize him as 'high-strung', although confinement/cat carrier/car rides are tremendously disturbing to him. He will wail non-stop and beat himself silly against the carrier during the ride.

We have learned to associate any unusual behavior following a vet trip to this stress. He is usually himself again within a day or so.

He had been himself again for a day or two, but now his behavior is extremely odd. He is quite lethargic, and he seems afraid to be alone. His gait seems slow and deliberate, like he is afraid to lose his balance. If you were unfamiliar with him you might mistake him for being quite old, except for the fact his coat is still vibrant and luxuriant, and he has all his teeth.

His face seems off somehow also. He has a droopy look, and his eyes seem kind of rheumy, almost unfocused. His nose is dry.

The vet trip is SO traumatic for him, we do almost anything to avoid them, but we are very concerned right now. Any ideas?

Answer
You really need to call your vet and get advice directly from him or her since s/he has examined your cat and knows him best.  This is NOT a typical reaction and there may be something else going on that warrants another trip to the vet and medication.