Okay, first and foremost, are you tracking your work movement as exercise? You are likely overestimating your calorie burn. It's okay, this is really common! So common, in fact, that Sparkpeople has a way to figure out what you need to do to account for this: www.sparkpeople.com/community/ask_the_expe
The problem with counting daily work activities as fitness is that your body adapts to the movements, and you're not burning as much as you think you are. If you were really burning that much all the time, you wouldn't need to lose weight. ;) You ARE burning more than you would at a sedentary job, but I would not count it as purposeful exercise.
Follow the steps in the above expert answer, and adjust your intake accordingly, but don't track that work stuff as exercise.