I was pretty worried about not getting the shot too, but when the doctor wanted to leave it out I figured it was a pretty big deal. Most vets really tend to over-vaccinate (in my opinion, at least!)... so when they suddenly turn around and recommend NOT doing it, I think it's important.
Is Oliver on steroids due to his reaction this time? Poor little pup. At least he's ok now. You might want to talk to your vet about using Benadryl next time anyway, our vet recommends it for every dog who has ever had a vaccine reaction of any kind just to be safe. We just call them for a dosage and start Tommy on Benadryl 24 hours prior to his shots and keep him on it for almost a week after. It has pretty few potential side effects for dogs, at worst it made him a wee bit more sleepy in the mornings.