it's the infamous three-week stall. You just got it a little early. Almost everyone experiences that - if you do a search for it on this site, you'll find over 17,000 posts on it (and no, I am NOT kidding...). Mine was weeks 2 and 3. During week 4, it broke and I dropped something like 6-8 lbs in about two days. Just stick to your program and stay off the scale for a few days if you need to. It WILL break - they always do - and then you'll be on your way again.