Hey Fawn,
I'd say, you need to set a reasonable daily calorie goal--and 1200 is
not reasonable for someone at your weight who is actively exercising--and then,
stick with the goal. Don't try to second guess the scale, you'll get it wrong every time.
Weigh once a week, at the same time on the same day, and only record that weight. Don't worry about day-to-day fluctuations--you can vary by pounds a day just be eating salty foods.
You didn't do your body any favors by going that low. Just use the tools you have to calculate how much you should be eating for a 1-2 pound loss per week. And be aware that most estimates of calories burned with exercise are too high. It's best to just take that out of the equation.
Jay