I just finished day 7 of P2. I have lost 6 lbs. I thought I wasn't losing fast enough so I decided to exercise. I walked for 30 mins. Today it shows I gained a 1/2 lb. I don't even eat 500 calories a day! I thought I would lose faster because I use to eat what I wanted and as much as I wanted. I haven't been hungry either. I started at 139 lbs. I only want to lose 20 lbs. Is that why? Because I'm not considerably overweight is this going to be harder? Help!