Hun - the average weight loss of any female on a vlcd is 3-4 lbs - just cos of the science of how many cals it takes to lose a lb (3,500) and how many cals you are saving by being on a vlcd, so you've done really well!!!!
How much did you lose in week one? Remember that it your glycogen weight, plus water and a bit of fat. You've just lost 4lbs of fat! (with a bit of water! lol)
Don't be disappointed - that's fantastic!