I won't think it's water weight, it can be caused by the sodium.
My biggest thought now, and what I always see many who go on a diet is they think that by eating less, they will loose weight fast. The truth is your starving yourself.
Try spreading your meals a little more, say 4 or five meals, while consuming the same calories you have quoted and continue to exercise. Your metabolism will slowly start increasing, and you will start loosing weight.
Don't let your body go into starvation mode.
Thanks. I'll try that.