Thanks for the advice guys. I did call the vet and he told me to watch her very closely tonight. If she started vomiting or showing pain, he told me to bring her right in. Otherwise, I am to call first thing tomorrow morning to get her in for an x-ray and possible endoscopy.
That was an awkward phone call to make at midnight, since the vet on call is the parent of one of my first-grade students. He probably thinks I'm a dork right now, but oh well.
