| Don't give up! The fact that you cannot do 30 minutes on the step mill means you still have a way to go to get in shape. Try some other cardio activities to break the monotony and to utilize other muscle groups.
But, more importantly, it sounds like you are burning more calories through exercise but eating more to compensate. Start monitoring your diet through fitday.com or some other mechanism and post exactly what you do and I'm sure forum members will be able to give you some specific advice.
Finally, ake a look at the stickies on this forum. There are a lot of exercise and diet stickies that should help you.
Good luck! | 
