Am I on the right track to losing weight?

I'm a 31 year old male, and about 6 months ago, I was diagnosed with testicular cancer. I weighed about 240 lbs and after the surgery, I gained some weight. I topped out at 275 lbs. I decided to see a nutritionist to help lose the weight. I'm on a high protien, low carb diet. I was also given some medication to supress my appetite. I started this diet in the beginning of February. In the first month, I lost 24 lbs, just by watching what I ate and no excersise. Since the beginning of March I began using a treadmill. I walk at a speed of 3.5 mph and do an hour, 6 days a week. I'm down to 237 lbs now. Am I on the right track and how long should I start seeing some of this fat melt away. One I hit 220, I plan on doing some weight lifting. Any suggestions?