
Firstly, and most importantly, go back to that vet and ask them to fill out a Suspected Adverse reaction form, because collapsing back legs after a vaccination is NOT right.
Vets should, and frequently do NOT advise that dogs CAN have an adverse reaction, and the problems resulting from these can be horrific. (One of my close friends dogs suffered illness for more than half her life, and died at the age of five because of this!).
Do not be at all surprised if the vet pooh poohs the idea that the vaccine caused it, sadly its unlikely to be proved, but until more ppl report these things, nothing will be done.
I would be very wary of taking this pup back for a second jab if the reaction WAS to the first jab. certianly, if it were my pup, i wouldnt be leaving it just two weeks, more like four, or more.
Take back the bag of food, that has probably cost youa small fortune and IMO its utter rubbish.
Make a list of your questions, if necessary, make an appointment to see the vet yourself, without your dog, to ask these questiosn, and be assertive!
There are a lot of 'industrys' out there, medicine, whether its vets or doctors is just one of htem, where the people you are expecting service from do not tend to get questioned much by their clients/patients, and as such often dont take to kindly to it. They seem taken aback that pet owners want to know details, wont assume that because they say so, they must be right. (another of these is tattooists, they get that 'god complex' as well, very annoying!)..... YOU are the client, its YOUR money, and YOUR pet, if you dont like the service you are paying for, walk, find another, but always question, asking questions never hurt anyone, not knowing the answers to some of these questiosn might well!
I wouldnt bother asking your vet about dog nutrition, vets are NOT nutritionists, they re there to fix ill animals, most of their nutritional knowledge comes from the very ppl who manufacture the bags of overpriced dog food they sell.
HTH , and i hope your pup is ok.
Em