Prepare to let her out every 5 minutes until whatever it is clears her system. And, sorry for the pun, you might just leave her on papers until it all "passes". Watch her for serious distress though, and if it gets too scary, take her to the vet.
Has she been around other dogs recently? Could be any number of things. (one reason I don't like "dog parks")
Yup, hard, tight, bloated abdomen, as redhen says, is a SERIOUS danger sign! get to a vet asap, I lost a Standard Poodle to torsion. From doing his roll-over trick.
Monitor her carefully, collect any stool samples for the vet if needed, (bless baggies!) and good luck to the baby girl!
With any luck, she just found something interesting to eat outside. Or maybe somebody slipped her some leftovers and won't tell you.
Let us know how she's doing, ok?
