Does she make the clicking noise when she is panting? Coby often "clicks" when he pants. It's the weirdest little noise. I often equate it to an old person's clicking when talking with false teeth.
As BRPrincess said, panting can be a sign of nervousness or unease. If she seems fine otherwise, she may just need a few more days to calm down. If not, or if you're still nervous, you may try to get her into the vet sooner.