Welcome to this WOL! First of all your lost is great! I only lost 9 lbs the first two weeks and was so happy! And it is common to go in spurts.. Lost 5lbs here.. none there. Your body is catching up after a fast loss. I've been doing this 12 weeks and only lost 17lbs. So your 18 loss in 3 weeks is something to jump for joy for! I am not sure but I think those ketostix to expire. I'd buy some new ones and see if that makes a difference. I used to use them,but have not for a few mos. I've been stalled for over a month ,but I have cheated this month too! Well best wishes to you and congratulations on your 18lbs!