Could be epilepsy. I had a boarder collie that had that. Also there is something called "small Dog Syndrome" where they shake very bad. There are meds. for these problems. I'd call a vet ASAP
My son's Beagle has seisures, which are very similar to what you are describing. The Vet prescribed meds, which have helped tremendously. It also could be epilepsy, as Reagan suggested. I also, would suggest you get her to the Vet ASAP, as some conditions that cause these symptoms can be fatal.
Yes, get your dog to the vet immediately!!!!
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them