I don't think you're being lazy, but most likely just tired! After having my daughter I was constantly exhausted for the first 3-4 months of her life. My boyfriend sleeps like a rock, and no matter how much he tried, couldn't wake up to feed her a lot of the time. So I was up night and day with our daughter. Look at your diet and see if you can change it to get more energy. I started taking barley grass a couple of months ago, and now I wake up with much more energy than I had before. Find a healthy way to energize yourself, and you will find yourself much more motivated to exercise more frequently.