Ativan and Xanax both are catagorized as Benzodiazapines, although they work a bit differently. A urine test wouldn't show the difference unless it was looking for a specific drug. The urine tests usually look for the presence of amphetamines, opiates, cocaine, THC, benzodiazapines, and synthetic opiates. Most workplace urine tests aren't sophisticated enough to look for a specific drug, unless you work for the government or a major corporation.
Considering benzos can be habit forming, you'll eventually need to increase your dose. They definitely mess with your memory, so perhaps you can find another way to chill yourself out.