Wolflady,
I have never had an experience like that before, but I wanted to let you know how glad I am that Marius is better. How old is he? And hasn't he had these same boosters before? I just find it so strange that they affected him that way this time.
I'm trying not to overreact about your vet from the tone of your letter. But were they caring enough in this situation? Maybe its just the way you said it, but I think based on that treatment, I might just try and find me another veterinarian. I have heard so many good things about "cats only" vets. We obviously don't use one since we have dogs and cats, but you might want to look into that. You might have a better response next time there is a problem.
Maybe Marius could have some wet (canned) food today in small amounts and you could gradually increase his intake if he's keeping it down. You know he must be hungry.
Good luck to you and to Marius. I know you were frightened. I am so glad you had your husband to assist and comfort you.
Logan