5 pounds in a month is more than good. That's great, actually. It sounds like you're doing everything right. If anything, you might want to bring your calories up a bit. Its possible that you're losing fat and gaining muscle. That's what I've been doing. I actually regained 5 pounds since I started going to the gym regularly, but my clothes are getting looser, so I know its just muscle gain. I just decided to quit weighing myself for a while.
Current Goal: Wear Size 10 Pants by July 1st