Okay, I have to say it. Time for a new vet, this one knows DIDDLY about toy breeds. PLEASE get a recommendation from someone in your area that breeds toy dogs.
The Nutrical/Karo/Syrup is not meant as a substitute for food, and NO you are NOT over reacting! That baby needs FOOD, the sugar is just to get him over the hump and get him eating again. Here is a formula I posted a while back that saved my Luna's life, after the pet store's vet told me to give her a full teaspoon every hour
You can read about it here:
http://www.yorkietalk.com/forums/sho...a+hypoglycemia