It's OK, we're all going to have those days when it's rough! Just remember why you're doing this and remember that you're stronger than you give yourself credit for being! Not only CAN you do this, you're GOING to do this!!
I agree with Mike, the busier you are, the less likely you're going to be running to the kitchen for food. Sometimes when I feel like I want to eat something I know I shouldn't I take a walk. It doesn't have to be a long walk, or at a really fast pace, just take a stroll! Also, be sure to keep plenty of healthy fresh foods on hand. That way, if you feel the urge to snack maybe you can grab a couple of carrot sticks or some fruit! That way you curb your urge to eat and not take in too many calories!
Another trick I use is to have a "goal dress" (or pants, shorts, outfit, etc) that I keep in plain sight in my room. Everytime I see it I remember what my goal is and what I have to do to get there.
You can do this girl! Keep the faith and stay postitive!!