First off, congrats on succeeding with following the plan your first week and making the decision to better yourself.
As for the loss, I wouldn't be worried. In my first 2 weeks I lost a total of 9lbs. About 2/3 came in that first week. And in the book Dr. A says you can expect 7-13lbs to fly away during P1. You may see a diminished loss this coming week. But don't let that scare you or discourage you. Following the initial drop, it should slow to about 1-2lbs per week. So in a nut shell, you are normal.