A 15 week old puppy is very young and if it had vomiting and diarrhoea and had a bug,then it might just have been wobbly because it was weak and dehydrated.It should certainly not be on a tablet for reducing fluid as it may already be dehydrated from the diarrhoea.
I would ring a few workmates or friends and just ask for details of a different vet,get the pup a checkup.
Give the breeder a call for advice and if the puppy has recovered and is up and trotting around normally,there is nothing to worry about.
Then put the idea of SM out of your mind and enjoy your puppy.Chances are there is nothing at all wrong with it.
Talk to your new vet about worming,vaccines and keeping the ears clean to prevent infection and mites.
Stick around on the board and let us know what the new vet says. Good luck!
Sharing my sofa with Holly, Ivy,Lilly and Hazy.. and never forgetting our beautiful Daisy who reached the bridge too soon.