5 lbs is awesome! I wish I had used a tape measure before I started, because I think the inches lost is way more than the pounds!
Go slowly into P2, as others have said. It's scary at first, but, don't worry, you'll keep losing!!!! I've lost all mine since November 6!
You are right though, exercise helps, and that is my resolution for 2008!
GOOD LUCK and stick with it!!!!