Sounds like what we call dry heaves. She is vomiting but nothing to vomit. Room temperature water with a pinch of salt. As well, is the dog overheated. This is also a cause. If this continues, get to a vet or call a vet. But give a bit of time, hopefully this will pass. Do you know if the dog got into any cleansers at home. If that is the case, need immediate attention