Will I lose weight or should I eat less?

I eat about 2000 calories a day. I try to eat as healthy as possible by eating a lot of fruit for snacks instead of junk food. It's so hard but I feel like im getting no where i been doing it for a week but I haven't even lost a pound yet! >:( I'm 5'7 200lb female. I use the elliptical trainer for 30 minutes everyday and I burn 500 calories per workout. Help! Tell me what I'm doing wrong. I'm afraid to lessen my calorie intake because I'm breastfeeding.