Weiner Dog Seperation Anxiety-Please Help

[chomper]

Hi There,
My Daschie has brutal seperation anxiety!!! He is fully house trained when we are home or at someone elses home, but when left alone he leaves little presents in the forms of tootsie rolls or a little Pee Spot. Even if he has just relieved himself!!! He gets very anxious when we leave either the house or car. He even gets anxious when someone that is not in the family leaves the car. Thanks for anyone that may offer help!!!!!!!