Ok, I'll be gentle here.....
First, your baby is definitely underweight based on that pic. Puppies are typically "ribby", but yours is also "hippy"and there's a clear indentation where the ribs end and the belly starts, shes too thin.
Switch your food immediately! Diamond Puppy food is not a very high quality food, the first ingredient is "Chicken by product meal"..which is basically the waste parts of the chicken not usable (nor identifiable), and then a lot of grains and cereals. The first "real" animal ingredient..(unnamed!) fish meal... is too far down the ingredients list. V's need a high quality, animal based food..compare "Nature's Variety Instinct Original"and see.
Visit "Dogfodadvisor.com"and pick a 5 star food, one with at least some identifiable meat meal as the first ingredient. And under the circumstances, I would suggest "Free feeding" so she gets the nutrients she needs to grow and develop properly.