I think you are probably just seeing fluctuations in the amount of water you are retaining. Drinking a lot of water and avoiding salty foods can help with this, but in the end, there's no way to completely control it. Water retention is impacted by so many factors other than salt and water intake: exercise, TOM, medications, stress, etc. etc. In your case, your body is still adjusting to a new diet and a new exercise routine; that is going to impact the amount of water it retains.
Weight loss isn't always linear; you can't expect that you are always going to lose the same amount every week and that once lost, lbs won't ever show up again. We all go up and down, all the time. But over the long term (and I'm talking months, not weeks), you'll see a downward trend. Sometimes I think the hardest part about losing weight is that it's GD fricking slow

; you have to be patient.
It sounds like you are off to a great start and I'd be hard-pressed to find fault with your diet; it's better than mine.

My advice is to just keep doing what you are doing and I think you'll see the weight come off.