Muscle weighs more than
fat. When you start working out, the
body will often start making muscle first because its the muscle that burns the
fat. That's why you weigh the same as when you started.
Try letting your clothes be a better indicator of your
weight loss than your scale. A scale won't tell you that your
fat has been converted to muscle, it will only tell you what you weigh. Your clothes will start fitting looser and you'll see more definition in your calves, thighs, etc.
Keep doing what you're doing, and the scale will start to show the
weight loss you want. It just takes more time for it to do so.