Heartbreaking, but true: When you head out the door, your dog may act out because he fears youll never return. Its like a child whos lost his mom at the mallhe just panics, says Marty Becker, DVM, pet expert at VetStreet.com. So why does it happen? When people bring home adopted dogs over a weekend, the pet sees his new family all the time, explains Collins. When the work week begins, he has to deal with hours of isolation, a stressful change. Though signs that youre leaving, like grabbing your keys and putting on your shoes, can cause your dog to chew the door, self-mutilate and more, dont respond to your petitll only reinforce the fear. The wrong thing to do is go, Dont worry, Ill be right back, explains Dr. Becker. Instead, pretend your dogs invisible. Then, at a time when youre not actually leaving, grab your bag and then put it away. Or go out, start your car and then turn it off and come back in, recommends Dr. Becker. This should desensitize your dog to your comings and goings. You can up the ante by giving your pet a treat when you pick up your bag or leave, so your dog associates you leaving with something positive. But if your dog just wont calm down when you leave the house, speak with your vet. A prescription for Xanax may help, says Dr. Becker.