You're fine as long as you're eating your points, and not nutritionally depriving yourself. I lose 5.4 lbs in one week and talked to my WW leader face to face and she simply said that sometimes it happens. As long as I wasn't depriving myself, or unsafely exercising it was ok.
Like others have mentioned, it won't last long. Eventually the body will stabilize and most people don't see those huge losses (or at least I haven't) when I finally got into the routine of the program.
I'm a big believer in listening to your body. If sometimes tells you its wrong: like you feel fatigued or dizzy then it probably is. If you feel fine, you're eating and doing what you're supposed to then I don't really think it's alarming.
Great loss btw!