The vet said that the vaccine might upset him a bit and he might get a bit of kennel cough in reaction but didn't explain what the symptoms were. Or he could just have been a bit upset by having his routine upset over the weekend. You aren't being dumb, you are being a concerned puppy mommy and rightly so you should be. Having a new baby in the house is challenging especially since they can't tell us what maybe wrong with them. You may want to try and boil an egg and give him a little bit of that to see if he will eat.
Eggs are easy to digest.
Hope this helps and let us know how things go. Terms of Service.