Our female sheltie is 3 years old. She gets very upset and stressed out when we leave the house. Some mornings when we leave for work she won't eat her breakfast because she anticipates that we are leaving soon and starts to spin and bark in a frenzy. Our other sheltie (10 year old boy) is her best friend and he is very calm. He knows that we will return later. We also have our dog walker who comes every day around 12:30 for a walk which they love. My husband and I remain calm and ignore her but this hasn't worked. Does anybody have any suggestions how to calm her down?