it sounds like you have been doing the same workout routine for a while. if you continue to do the same exercise for long periods of time your body will eventually hit a plateau and the exercise will stop being effective. i would increase your cardio to at least 60 minutes and mix in different activities, such as swimming or jogging. interval training is also a great way to burn calories and raise your metabolic rate. also, don't forget about the important anaerobic (muscle building) exercises that help tone your body and build muscle, which in turn will increase your body's metabolism.