I like Royal Canin for Yorkshires. It is made for Yorkshires sensitive stomachs. Has the omegas for the coats, ect.. As far as her weight if she seems to be under weight, you can try adding a half of a teaspoon of sour cream to her diet about three times a week. I just add to the food and stir. This help produce fat and has calcuim for her to boot.
Not to mention your dog will love it. If the vomiting persist after changing her diet to a formula for sensitive stomachs I think I would take her to vet to make sure there isn't a underlaying problem. I too, am a worry wart.
I am sure the vet loves it though. But these babies look to us for their care and they deserve the best we can give them, to repay them for their unconditional love they give us. Sorry for your loss. I will put you in my prayers. Be blessed and let us all know how your girl does. Sue