Drooling, Panting, Ears Laid Back

Question
Zoey is 18mo. outdoor lab.  We live on 20+acres in MT. She came in today after her usual 1 hr. outing. She is drooling a clear, thick saliva, panting, ears creased back/tense, looking out the window "owl-ly" -- usually lays on couch or bed. Won't eat dinner.

We checked her mouth. No physical signs of any "attacks" by anything.  She is very tense & seems spooked by something.
We called our vet;plan to watch her tonite - Any thoughts?

Answer
It is hard to say what she may have encountered, wildlife, plants, intruders, trash?  I think you have done the right thing.  I would stay in touch with your vet and run her in if she is still the same in the morning.  For most Labs, not eating is serious.