It's the exercise, baby. Your muscles will hold water in order to repair themselves. And please keep in mind that:
1. Time-based goals just aren't realistic. Seriously. All you can do is be on plan eating and diet-wise. You can't control how fast your body loses the weight. You might have had a hard exercise day, or eaten too much salt, or be near TOM...IMHO, time-based goals lead to nothing but frustration.
2. Patience! This takes time...see point above!
3. Are you changing your lifestyle? Or want the numbers down? There are alot of plans that get the numbers down, but don't teach you how to maintain the loss. Other plans let you change your lifestyle, and as a RESULT, the numbers come down. Different focus. It just depends what your path is.
Just some things to think about.
PERSONALLY, I think you are doing really well. Hang in there. This WILL work out for you. Just breathe...
Kira