We got our puppy 2 weeks ago and she was 2 lbs 12 oz. And she went to the vet yesterday and is now 5 lbs. She was eating 1/4 cup three times a day. But the vet said she needs a cup a day because I told him she acts like she has never eaten when I go to feed her. She is chunky!! She is on Purina puppy chow but this weekend we are getting her Blue Buffalo. How much should I be feeding her?