I would take her to the vet. Ear infections can flare up very quickly and be extremely painful, causing some dogs to become quite snappy with the pain. Good luck.
my nans mini poodle was like that he was at the vets all the time as he was always scratching and rubbing his ear against the floor,something aparently common in his breed.they used to clean his ears out with salty water with cotten wool balls.dailey. it seemed to help! you could try that