Q: My little poodle-bichon mix began trembling quite intensely recently. The trembling is so intense that it feels like her little heart is going to explode. Is she afraid of something or sick? Why is my dog trembling?
A: Your dog could be trembling for a variety of reasons. While it is possible that she is scared of something, it seems unlikely since you describe the dog trembling as intense.
Your dog's trembling could be something neurologically related.
I think it is very important that your dog be examined by a veterinarian. They can perform routine blood tests to check your pets' electrolytes, blood sugar levels, etc. It is a possibility that your vet may wish to refer you to a veterinary neurologist if they feel that it is necessary.