I was where you are after three weeks (21lbs down) which is great but I felt exactly the same as you do now as I only lost 2lbs in my third week. Almost five weeks further down the line (my week 8 weigh in is on Monday) and I'm on target for another 17 or even 18lbs off. That will be 38 or 39lbs in just eight weeks - almost three stone!!! I know it's hard but try not to focus too much on the weekly losses which could vary for any number of reasons, but take the longer term view. The small losses add up too. Stay determined and celebrate every pound off as each and every pound takes you ever nearer to your goal. Good luck for week 4.