Did you get her to the vet? It could be a number of things. Too many to even try to guess at. Let us know please, and I wish you and your baby lots of healing vibes!
Agree with blu. Is the dog up to date on all shots? Any chance she got into something inside or outside? You may want to look around. Hope you get to the Vet and all will be ok.
Take her to your vet first thing in the morning and have her tested for parvo. Even tho she is not showing all symptoms of this, maybe it can be caught early.... dogs with parvo who go without treatment die, every one of them. And she could just as easily just have a tummy ache. I say better safe than sorry and take her to the vet as soon as you can. Blessings for you and your dog - Blu