I hope Minion feels better. Unfortunately, digestive upsets often have no diagnostic cause (there's even a special word for it) but the symptoms hopefully can be treated. Smokey the Elder lost a lot of weight, yet had normal liver, kidney, sugar, etc. We fed her a bland diet, gave her cimetidine (antacid) and she got better after awhile.

On the vaccination angle, at least one vet in the area is now offering three year distemper shots once a cat has had its kitten series. The next year, he can get a 3 year distemper and 3 year rabies. This will cut down the possiblity of VAS or other reactions. Also, the manufacturers are modifying the formulas. Often, it's the stuff other than the active vaccine ingredient that causes the reaction.