4kgs in a week sounds alot hun but the rest sounds pretty normal. With DD I put on 15kgs and with DS I put on 20 kgs. Both were big babies, 4kgs and 4.5 kgs, and I carried heaps of fluid but I lost it all both times in a fortnight. Having a c/s too I found my appetite wasn't huge, I drank heaps of water while b'fing and it just fell off. (Having said that I didn't keep it off If you keep losing weight and are finding that you aren't hungry etc I would go get some tests done. xox