Have you tried tinkering with your calorie intake? I had exactly the same problem and then increased my calories (I was only getting 1,000-1,300 on an average day). Lost 4 pounds the first week, then stalled again for a few weeks till I charted out my FitDay entries and realized I'd gone right back to undereating. Readjusted my calories again, and started losing immediately. I've decided I'll do whatever it takes to keep it at 1,750-1,900 a day for now.