Hey there Mrs. D...
Everyone's body is different and there's something going on that may be slowing you down a bit..
That said, your body is reacting to the fact that you're changing your eating habits.. Sometimes after a successful Take Off, the body reacts by retaining water and holding on to anything it can..
Also, you will eventually learn to get into a groove with when you go in for your weigh ins and stuff like that.. When you go in absolutely affects the results on the scale.. Try to develop a way to get in there at the same time, each time, with the same clothes if possible.
The amount you exercise also absolutely affects your weigh ins. Make sure your counselors know what you're doing, because it may affect the plan you're on. Also.. When you work out, follow each session with a lean protein and a good carb, like fruit.. That maintains the calorie burn.
You also need to channel that frustration to something else and not give in to the temptation emotion eating provides.
We who have been on the program a while have realized that the feeling we get by NOT giving in to the junk food far outweighs the momentary pleasure we get from the taste of it.
Also, don't get back on track tomorrow.. Get back on track NOW.. Screwing up on one meal isn't the end of the world.. Make up for it the rest of the day be having only light proteins and get in all your fruit and veg portions.. Sounds like you're done with starches for the day anway.
The iron pills may have something to do with it too, but I don't know..