Oh goodness, poor baby
! Agree with Dwerten - tests needed!
She is very tiny, so I'm glad you're heading to the vet, you truly need to w/ this much throwing up -- she may need IV hydration. And you're correct, she may have aspirated some vomit so be sure and have the vet listen to her lungs.
Also fyi, Metro (flagyl) can be
very tough on some dogs, so personally I'd hold off on giving it this morning. More info on Metro:
Metronidazole For Veterinary Use
Please keep us updated, I'll be hoping for some news, but definitely get this little one back to the vet ASAP.