Have you had him checked by a vet? Pacing, panting, whining and not eating can all be signs of pain or illness. I don't think that 3 months after the move he'd be having a delayed stress reaction. Best to have a vet check him over and make sure it's nothing physical.
Has he recently had his tail caught in a door? Our Ember broke his tail trying to let himself out one day and got very pacy and whiney from the pain, so that's a possibility, too.
Hope he's better soon!
