Definatly the vet asap
I hope everything is okay. That sounds very very scary. I would try to get ahold of the breeder, maybe she would be willing to keep the pup with mom for another month or so. But either way a vet visit is in order. At least you can talk to the breeder about what happened, and if this is the first time it happened.
Has she been eating well since you got her? What is she eating?
Did this happen yesterday or today?
How is she acting since this happened?