What is wrong with my puppy?

my puppy wasn't eating Sunday and she was moving around less than she use to (she is very hyper) so we cook up some meat and cornmeal for her when she finally ate she was back to her old natural self running barking and playin. yesterday she fed her again but later in the evening i notice she vomited up little of the food and her stool was soft and little watery but she was still little active and barking. now today i went to check up on her and i saw white foamy vomit and little of the food she ate, what could be wrong with her ?im cooking some rice for her will that help?