Is Excercise Worth It?

I work out doing Jillian michael's 3--day shred everyday and it deosen't seem to be doing anything. I eat no mroe than 1500 caloreis a dya usually. Nothing has changed. I look the exact same way as I did befroe I did this workout(except for ym arms which are becoming more muscual than i would like) Can anyone explain this? I'm trying to eat healthier, but I stay within my calories.Please help!