Dreams involving pets, especially dogs, often symbolize loyalty, companionship, and protection. In your dream, your dog falling down a mountain could represent a fear of losing something or someone important to you, or it may reflect a feeling of vulnerability in a situation.

The act of your dog running back to you and jumping into your arms suggests a strong bond and a sense of reassurance. This part of the dream may indicate that, despite challenges or fears you may be facing (represented by the mountain), you have support and love that will return to you. It could also reflect a desire for safety and comfort in your waking life.

Consider the current circumstances in your life. Are there areas where you feel uncertain or anxious? This dream might be your mind's way of reminding you that you are not alone and that loyalty and support are present, even in difficult times.