Hi Jkhan7270,
Welcome to alli! As you probably know, exercise is a key component to losing weight. Due to the decrease in calories in your diet, you're probably lacking the energy you usually have. After a week or so your body should start to get used to your routine and calorie consumption and you'll feel like you have more energy.
You must make sure that you are also getting enough sleep. If after a few more days you are not feeling like you have enough energy to exercise, post your problem to the regisitered dieticians on the site. They might be able to help you fine tune your diet to the point where you'll start to have more energy.
Good Luck,
Paul