I can so relate with that. I started Spark two months ago. The first month was so depressing because I gained a couple pounds and my weight kept fluctuating, it was driving me crazy. The friendly posts in response I got was incredible. It helped having real people tell me it WAS working. Don't give up. They also explained I was probably gaining muscles, which I was because I was firming up.
So I hid the scales for a month and bought a tape measure and in two months I've lost. 4 inches!
plus I have a lot more energy. I feel awful if I don't walk at least 3 miles a day. And I want to do so much more.
Don't give up because you are making progress. No matter what those scales say, you are doing great.