Losing 40 lbs Post Pregnancy...

Two months ago, I was blessed with a beautiful baby girl... however, not so blessed with the additional 40 lbs that I gained during pregnancy. I gained a total of 159 lbs with the baby and lost nearly 20 lbs in the first month and lost nothing the second month despite breastfeeding. Before getting pregnant, I was 5'0 and 100 lbs and actually training for fitness competitions. I was 100 lbs of all muscle and had a six pack. However, when I got pregnant, I let myself go and have gained a big whopping 40 lbs and now steadying at 140lbs. :(

I've never been this big before in my life. After my first pregnancy, the weight melted off because I worked full time as a waitress at a casino so the constant running around led me to lose all of my baby weight in 2 months. And when I was skinnier before pregnancy, it was easier to just exercise and get fit... now, I feel that no matter how much I count calories and exercise, the weight isn't coming off fast enough. Help!!!!