Please keep in mind that muscle mass weighs more than fat. If you are walking that much per day, you are very likely to be building muscle as well as burning fat. A better method to determine whether or not you are losing body fat would be to either tape your body (waist, thighs, hips, bust, upper arm, etc) and measure weekly or bi-weekly to see if there is a change. Another, and better, way to measure this would be if you join a gym or have access to someone who can actually measure your body fat percentage to have that done and continue to have it done every few weeks.
I would also suggest starting a food diet. Please keep in mind that with that high of an activity level, your caloric need is going to be greater than someone with a sedentary lifestyle. If you drop your caloric intake too low for your activity level, you will slow your metabolism because your body will then try to store the fat for fuel.
at 1:50 AM on May. 22, 2009