I stayed the same for two weeks and almost gave up hope, then lost 6lbs last week. The key is deffo the water and a bit of gentle exercise too. Wait until you see the results next week!
Also, try not to look at weight loss on a week by week basis, look at it month by month, then you'll see how well you are doing. It's easy to get fed up but the losses are great in the long term, and for many, in the short term too.