Try eating only things that have the nutritional information on the box, can or bag. Don't try to guess. If you're concerned about nutrition, have an Advantage shake for breakfast, or Muscle Milk, or any other liquid supplemental meal. They're all very similar. Have a frozen meal for lunch. Have one for dinner. Keep track of the sodium and try not to go over your daily requirement (reported as a percentage on the box or can). Be mindful of servings reported on the can/box. Drink plenty of liquids - water, preferably, because it has no calories. Then, after a few days of careful tallying of THOSE prepared meals, see what your weight loss is. If you're losing weight, then tracking and measuring is too tedious and that's where mistakes are coming from. The pre-measured meals are safe.
Also, check to see what your target caloric intake should be, for your height, weight, and age (fitday has a tool for this). Weight does not come off in a linear fashion. Hormones play a part and water-retention, for example. But if you stick to it, the weight will come off.