The dog needs to be seen by a vet to be accessed properly. It's very concerning this has happened more than once accompanied with shaking. A full blood work up and assessment would be helpful in getting to the root of the problem. Please make sure that she follows up with a vet visit. Today preferably!
As for free feeding, I feel it is hard to keep track of the amount of feed consumed. Additionally, Pebbles while younger developed a guarding issue that is very hard if not impossible to correct. Please update us after the vet visit. I will keep the little guy in my prayers.