In general vomitting is not as serious to pups as it can be to humans. Both of mine vomit every once in a while (in fact, Shelby did yesterday, and I think it was an emotional thing because I was very busy yesterday and both pups were upset with my lack of attention).
That said...it can be dangerous to a young pup. It can cause dehydration. Sometimes a pup will vomit in the morning because of an empty tummy. Some advice giving the pup a biscuit before bedtime so they aren't sleeping on an empty tummy.
How is she behaving otherwise? Her gums should be pink. If you press on them they should go white and right back to pink. If they aren't pink it can be a sign of dehydration.
Loving mom to Jake, Shelby and Micah