It's frustrating you because you are letting it frustrate you -- because you are letting it rule how you feel about what you are doing. Throw it out. I'm a JC'er, too. Let the weekly weigh-ins at the center be the only weighing you do and you'll be a lot happier. Even then, don't pay too much attention to it. The people who get all wrapped up in the scale, and let that number drive their attitude about the process, are the ones who give up really quickly. I agree that shows like Biggest Loser are a real detriment because of the emphasis on that number -- that is NOT the way to approach life-long weight loss and maintenance.
I'll tell you something -- I'd been derailed by that problem so many times in the past that when I started JC I got on the scale backwards every week and didn't even look at my weight! I knew that if I did all the right things, the weight would come off, and that I needed to concentrate on ME, not my weight. I needed to work on the thought process and habits that made me overweight in the first place, and devote all my energy to that rather than worrying about the ups and downs of the scale. The truth is that you never lose as much as you want or think you ought to, or that you think you need to "stay motivated." On the rare occasions where that number is better than you hoped, it just sets you up to expect the same thing next week. And, the scale is GOING to fluctuate. You are NOT going to lose the same amt every week like clockwork, it just doesn't happen that way. I had no idea how much weight I'd lost until 6 months had passed when I finally decided to get on and look at the numbers. If you notice, I don't have a ticker or my weight info in my signature because I don't want to give those numbers power they shouldn't have.
Let go of the scale, it's not your friend.
Here's a very helpful article on the technical side of the subject:
Why the Scale Lies