I just wanted to mention that my sister is doing Atkins and like you she is VERY active. In the Adkins book it does state that if you are already doing an excercie program, you should not stop. She didn't and had a really tough first week, but by the second week ~ she said she was back to her old self. Maybe you could try to slow down a little for the really bad days.

I only walk for excercise and I did not give it up either and I felt fine ~ except for a couple of icky days.