Slow Loser? Help?

Hey Y'all! I went to my dr yesterday and here are my weight loss results: Started LC June 07 at 218 pounds. Drs Appt: Sept 17, 07 weight: 197 So in 2 1/2 months, my loss was 21 pounds. Not so bad. YESTERDAY, 5/05/08, my weight was 172. So from 9-17-08 - 8 months, my weight loss was only 25 pounds. NOT SO GOOD. I am eating clean and doing Callanetics as much as I can. I'm confused why my weight loss has slowed down so much and I still have 50 pounds to go and I'm not cheating!!