You've mentioned exercise but nothing about diet. Weight loss is at least 50% diet and many say it represents an even bigger percentage than that. And with a bit of preparation it doesn't take any more time to eat healthy food than unhealthy food, which is great if you have a busy schedule.
Is there anything about your eating habits that have caused you to gain weight? Even a healthy diet can keep you large if your portions are too big. Hell, I managed to gain 20kg on a vegan diet for just that reason! You might want to check out these articles here
. You may find you're overeating without realising it! Remember not to eat until you're stuffed, even if it's very healthy food. You're just training yourself to overeat otherwise. Eat until you're satisfied. You can always go back and have a healthy snack when you're hungry in a couple of hours. Don't stuff yourself silly 'just in case' you get hungry later. You're supposed to get hungry later after all! That's why we eat more than one meal per day!
The trick is to eat enough to keep you satisfied for just a couple of hours. Then have a healthy snack like a piece of fruit when you start to feel hungry again. It will stop you getting too hungry so you won't pig out at dinner time and will keep your metabolism up so you burn more calories.
Another way to monitor your diet would be to use Calorie King
. Many people here swear by the site. It's free and when you set up your profile it will recommend how many calories per day you should be eating. Then you can either follow on of their set diet plans or enter your own food and see how it all adds up.
Even if you don't use their food tracker religiously it can be useful to use to find out what foods are lower in calories and fat.