I think it could be either she's nervous or cold. Missy will shake like that out of nervousness when I'm taking her to the vet. I don't know how she knows that's where we are headed, but she does. She doesn't shake when we drive anywhere else. The only other time I notice her shaking is when she needs another layer of clothing on. She's always dressed, but sometimes she needs a hoodie or jacket over her outfit even in the house. I guess when you're 3 lbs you get chilled easily?
