I would be concerned that Reilly has hurt his back or has an inflammed disk in his back. Dogs with back pain will not want to move or jump, may sit somewhat hunched over, but will still try and eat. They don't want to be touched because they are afraid it is going to hurt.
Disk disease can be very serious--if the disk should completely protrude into the spinal canal, it will put pressure on the spinal cord and can cause paralysis. We generally treat disk disease with muscle
relaxants (because their back muscle are so tense) and either a non-steroidal anti-inflammatory or steroids (vets have different preferences). Confinement is very important to keep the dog from causing further problems as he starts to feel better.
If the dog becomes paralyzed or starts dragging his rear legs
, emergency surgery may be needed. Most dogs, however, recover and do well with just the rest and medications. I have sent several dogs to a vet chiropractor and they have had good outcomes, too.
So tonight I would confine your dog to a crate or very small room and put a nice blanket on the ground for him to lie on. Tomorrow I would get him in to your regular vet for an exam. If he seems really uncomfortable tonight or has ANY difficulty walking
, I would take him to an emergency vet. This would also enable you to get him the pain medication sooner. I can't recommend you give him any aspirin, as it will interfere with the steroids or NSAIDS that the vet will prescribe.