Thanks to all for your help. We did make it back to the vet Tuesday afternoon. Both dogs were placed on Medrol and I was told to continue with the pepcid. By Wednesday morning, both were interested in food again, and everything has stayed down since then. Today and scratching and chewing stopped. The vet felt pretty confident that most of the problems were stemming from seasonal allergies. I still don't understand how that was the cause of all that throwing up though...
I'm not sure what happens when the medicine is all, but for now everyone is feeling better.
Thanks again for your input!