McKinzie, GET BACK ON PLAN! RIGHT NOW, WITH THE NEXT PIECE OF FOOD YOU PUT IN YOUR MOUTH! Most likely, most of that 8 lbs is water retention and will come off easily, but if you continue to stay off plan, you know what will happen.
Also, you need to figure out why it happened. Do you need to have a snack in the afternoon before you leave work to keep from being so hungry? Can you drink a big glass of water an hour or so before you leave work and maybe refill your cup for the drive home? Fiberlover had a great idea about the cash and debit card. Maybe make an appointment with a friend to go exercise or go for a walk right after work. You can't stop and eat if you know you have to meet someone someplace. Make sure you have at least one healthy, quick, easy to prepare, low calorie dish that you can make in a pinch at home, so you can't say that eating out is easier than cooking. Do everything you can to make it as easy as possible for yourself. Plan, plan, plan.
You can get back on plan. Why don't you come back here after work today and let us know how you did? Knowing that you have to be accountable to someone is a big deterrant sometimes.