I gave him his first antibiotic (Primor) on Friday after he got back from the vet, and he wasn't feeling very well Saturday morning, he didn't want to eat, kinda had mushy poo, and was just not acting like himself, he did eat that evening... Sunday morning he was again not feeling too well, but was ok by Sunday night, today he is a little worse, and didn't eat either of his meals, and now has the runs (he is drinking good though)... he's just wants to sleep or pace around, either panting or shaking at times. I called the vet and she said to not give him his Primor tomorrow morning and see how he is, if he is fine then she will switch his antibiotic if he is not ok, then I will bring him back to the clinic. Poor boy!