Exercise???

At my recent post natal checkup, I learned that I have lost all but 5 lbs of my pregnancy weight. Which is excellent, no doubt. But I know these last 5 will be hard. They are hanging out right over my uterus, adorned with a lovely forest of silvery pink stretch marks. The Doctor congratulated me and after my exam said " just don't resume heavy exercise until the baby is 8 weeks old". Apparently this woman is under the impression that I actually participated in heavy exercise before my baby was born. Granted, there was high school, when I was incredibly fit due to all of the dancing I was doing, but since then, I have been a member of 2 gyms which I went to like twice a month or something. I have the good fortune of looking like I am in shape, but I am definitely not. A few months ago, I could use pregnancy as an excuse as to why I got winded walking up the 3 flights of stairs to our apartment. I am not sure what excuse I am supposed to use now. I know one of these days my luck will run out, and since I'm a big fan of Coldstone Creamery, I suppose I had better find some heavy exercise to participate in before that last 5 pounds turns into 15.