We have a 10 week old Toy Chi who suffers from severe separation anxiety. I am about to go back to work from a layoff. Everyone including the vet recommended we get him a companion. Well we did just that. We bought a 4 month old Toy female. Thinking she would be a little older, calmer, she is crate trained...it would be a good idea. She came home today. I do understand she is scared, but she is VERY NIPPY, and has actually tried to attack the puppy. She was fine with him at first, but when he tried to play with her, she lit into him. She has herself tucked into the corner of the couch and will not let anyone near her. She came from a household of other dogs! I know everything's new to her, and strange. How long will this last, and what should we do?