Being completely honest, start to wean yourself off those scales....believe us, they are not your friend!!! They are leading you into a false sense of security that will turn on you later down the road!!!
This is such good advice (we're not ganging up - honest

) but this journey is about so much more than numbers on a scale. Yes, it's great to see the numbers drop but there are other indicators too ... inches, energy etc.
Like you, I was a weighing fantatic. I weighed myself not just once a day but EVERY time I went into the bathroom. I was curious about the amazing ups and downs throughout the day. And of course, the week one result was fab and I was chuffed to bits. Week 2 was a bit of a disappointment at just 2lb then in week three I only lost 1lb and almost blew a gasket.
A very wise lady on the boards advised me to get rid of my scales: I did and never looked back.
We drink a LOT of water on this diet and it can really mess up the figures i.e weeks we've lost FAT but not lost much WEIGHT because of water retention. There is only ONE weigh-in that matters and that's the 'official' one at your CDCs. In fact, even THAT becomes less important as time goes on. Our weight is only ONE factor.
I've been off the diet for a couple of weeks and I know I've been a P-I-G ... consequently, I KNOW I've gained heaps. I know because my clothes are tight. So when I go back to my CDCs on Jan 8th, I've decided NOT to get weighed but wait until my clothes have loosened up again: I know how disheartening numbers on a scale can be.
That aside though - I'm not detracting from how you must be feeling today with 4lb already gone. Keep glugging that water and the fat will just melt away!