While being on the pill may slow down weight loss, it should not stop it completely!
I agree w/Sherrie that you may not be following the plan correctly and consequently not losing any weight.
Perhaps you can post some of your menus/daily eating and we can offer suggestions? Have you read the book and are you following the induction rules and eating from the acceptable food lists?
You might also (if you don't already) get an account at www.fitday.com
to track your calories, fibre, fat and protein.
Hope we can help you out!