Losing that baby weight!

I just gave birth to my 6th baby! After I had my 3rd, I lost all the baby weight plus some and I was so proud of myself. I worked hard, watched what I ate and made sure to vivit the gym a few times a week. The weight just fell off. I havn't really put a lot of effort into losing this weight yet. My baby boy will be 4 months old in just a few days and I also have an 18 month old. Having 2 babies back to back has done a number on my body! The summer is coming and I'm not looking forward to wearing shorts and tank tops with all this extra weight on. I have 60+ lbs to lose. I've joined a weight loss group called "My Mommy's a loser" and if I lose the most weight after 10 weeks I will win over $100 in gift cards. There is also a weekly prize for the person who loses the most weight that week. I would like to lose 20lbs by the end of my 10 weeks. Tomorrow will be week 2 and I'm sure I havn't lost any weight since I weighed in last week but we will see.