Hmmmmm...torbutrol is traditionally used for pain but it can also suppress coughing in dogs. If your dog has those symptoms, I would stop using it and contact your vet for an alternative medication. It sounds as though he may be having an adverse reaction to the medication. It can cause them to be sleepy, but, if he is staggering, it could be an allergic reaction.
Some vets will vaccinate when an animal has sneezing or congestion as long as there is no fever.....I personally wouldn't do it to one of my animals as I feel if they are already fighting off something, vaccinating can cause additional stress to the body and make them show symptoms of the disease they are being vaccinated against.
Until you talk with the vet, honestly, I would stop all the medications until you can determine which is causing the symptoms you are seeing. There could be reactions to any of them, although to the benedryl, I wouldn't expect that. The antibiotic OR the Torbutrol could be causing his glassy-eyes and stumbling.
Please let me know if I can help further.
Canine Health Care & Guidance
Qualified by many years of healthcare & experience in breeding dogs