Why is my dog shaking and panting?

That does sound like anxiety. Is he still acting that way?

Dogs shaking or shivering can be caused by a variety of things. Is it when you are present or when a stranger, loud noise, or maybe at the veterinarian's office?

If the shaking occurs during the winter time and they are a short haired breed of dog they may be chilly and a dog sweater may help. Small dogs and nervous dogs often shake or shiver because of fear of strangers. Many Chihuahuas do this. You may want to try either giving Bach's Rescue Remedy and / or using a commercial dog pheromone called Adaptil in a spray or diffuser form. Adaptil is not to be put on the dog but used in his surroundings to make him feel more secure. Follow label directions on whatever you use.

Panting is a different story. I would probably have to see what is going on, but in general a dog panting is much better than one that is holding it's breath so to speak. Dogs naturally breathe through their mouths so panting is a good thing. If their mouth is closed the dog might be frightened. You can usually tell this is the case if you calmly wait for them to open their mouth to pant. If after a period of time you hear them sigh then you know something scared them and they are finally relaxing.

You can always check with your veterinarian if you think something else may be going on. A Fear Free Veterinarian works to call fear, stress, and anxiety in pets and may have the answer you need. Look up on in your area at http://www.fearfreepets.com/fear_free/directory.aspx (http://www.fearfreepets.com/fear_free...).

Did anything happen? This could potentially be a pain response. It could be anxiety, or stress but If you are at home, my bet would be pain. How old, and what kind of dog is it?