How did you lose baby weight?

I am 22, my daughter was born a few days after Christmas...she is my second child..I was 130 lbs before I got pregnant. I weighed 148 lbs when she was born... ...I now weigh 165 lbs... I fed for 6 months and lost no weight.....I'm sure it didn't help that I craved triple cheese burgers from wendy's while pregnant....But, I don't understand why the weight won't come off...I will lose like 5 lbs but just gain it back in a few days....I try to do 30 minutes of my kickboxing/dancing dvd 3 times a week...but that doesn't seem to help...and it doesn't even seem like i am losing fat and building muscle either....what worked for ya'lls and how long did it take to lose the baby weight?