She just may have a temporary tummy upset. I would offer her a handful of something in a couple of hours. You may want to take her temp and should watch her for any symptoms cropping up.
Will she eat treats? When they won't take their favorite treat, there's usually something wrong.
Sometimes they just don't want to eat. She won't starve missing a meal or two, but if she goes more than a day, I would call the vet.
When Piper first got the pyo, she was reluctant to eat, but had no other definite symptoms. So you need to be vigilant. Use your instincts and if you are worried, it's worth the vet visit to put your mind at ease.