I don't have any magic answers for you, but wanted to let you know that you are not alone! I am also breastfeeding, have restricted my calories to 1600 - 1800, have been exercising, and drinking my water, and SLOW progress. I'm a very impatient person, so it's tough to keep telling myself that slow progress is still progress.
I know with my first child I didn't lose a single pound between the time I gave birth until I was done breastfeeding (6 months later). With this child I have been able to lose, but it's been slow.
Some women can't lose weight while breastfeeding, even though all the logical steps for success are taken.