Glad your puppy is feeling better! I would suggest making sure he doesn't get any human food. Some dogs have very sensitive stomachs, and eating something we eat causes them to throw up some. Also, (and this is a bit embarassing), Bender had a problem like that due to hair. Not his hair, mine. I had long hair (thick and curly) and I used to shed worse than any dog
Well, we had hardwood floors and Bender would go around eating my strands of hair, and after awhile he would get this huge hairball worked up in his throat, and when he ate it bothered his throat and he'd gak up the food and some hair. I'd imagine you would have seen some hair in the throw up if that had anything to do with it, but just a heads up to anyone with long hair with a yorkie. I now have only shoulder length hair and carpet, Bender seems a lot less hairball prone
