Maybe ask them at the obedience school, what they suggest. Is it a lot cooler there? Maybe you could try a humidifier at your house. Maybe there is something in your house she is allergic to. Maybe get a second opinion from a different Vet. "just threw a few things out for you to ponder"
"You could have the worst day in your life, but when you go home to a German Shepherd it always gets better"