Here is a Spark article I've had saved in my favorites for a long time: www.sparkpeople.com/resource/nutrition_art
Losing weight is not an exact science. It seems like it would be pretty obvious, but it really isn't. There are so many factors (like the article explains) that contribute to a loss, a gain, or nothing at all.
You haven't tracked your food for the last couple of weeks, so I'm not sure what your calorie range is and what you're actually eating. Are you keeping track of it elsewhere? I've found that tracking my food is my #1 path to success. Have you tailored your plan to fit you? (You may want to lose 2 pounds in a week, but if that drops you to fewer than 1200 calories, Spark won't let you do it.) Are you eating enough for the fitness you're doing? (Talking a walk around the neighborhood burns fewer calories than something like Zumba, and you need more calories if you're doing something with a high intensity.) Revisit your plan and reset it if necessary to make sure you've got it all squared away.
Aside from the scale, have you noticed anything else? Inches down? More stamina? The scale weighs everything in your body, not just fat, so consider tracking things other than your weight.
Keep pushing - you can do it!