We are back from the vet and just waking from a long nap. The vet tested his blood cell count and some other test with his blood. He did have some slight damage to some of his blood cells and the red blood cells were already re-forming. She doesn't feel that anything serious will come out of this since he was treated early.
I called the Super Supper place where I had picked up my dinner (or maybe I should say Chase's dinner) from and they said that there may have been about 1/2 cup of onions in the mixture.