But you are down 4 pounds overall which is fantastic. Our bodies water weight goes up and down for many reasons and who knows why you body retained water the second week. You also may have lost some fat/inches. It's a jumpstart and you just have to keep going. Persistence and patience get you to goal. We don't lose every week (or you are seriously lucky if you do). I knew someone who lost 2 weeks, and gained, 2. This happened over and over. but overall she was down more than she gained each month. so just keep going and don't let anything deter you.