There is no doubt that dogs are tuned into our emotions, and particularly stress. We had a very stressed out little terrier a few years back. He would completely freak out on a walk if a car would pass by. My wife was concerned he would get hit, so she would tightly grip the leash as soon as she spotted a car in the distance. The dog sensed this and became more stressed. I started walking him with a very loose grip on the leash. There were a few false starts. It was also difficult to keep calm AND hold the leash loosely when a car would pass, but it worked. Within a few weeks he was walking fine.

yes, I notice this with my cat too. We seem to vibe off of each other.