Something to keep in mind is that a given volume of muscle weighs more than the same volume of fat. What this means is that as you strengthen and replace fat with muscle, you may not lose significant weight until your metabolism picks up from the increase in exercise. At 4 months, this should have occurred already so I doubt that's the issue.

As countryrider pointed out, don't let yourself get hungry. Make sure you have some low fat foods available to snack on and if you start feeling hungry between meals, nibble on them. That's something I am working hard to correct, because I'll get hungry and then shove some serious groceries down my throat. You then ahve a lot of food to digest, so you process it slowly. So the idea is to eat less more often.