I know that has to be hard. My bf and I did the long distance thing (though the story for us was way different) for over 5 years.
Find other ways to vent that are not unhealthy. Go for a walk/jog. Read the success stories here on 3FC. Come here and post. Give yourself a manicure/pedicure (or have it done professionally if you can afford it, I can't so
). Work a puzzle. Do anything that will keep you away from the food (well, away from food when you are not hungry and the such since you do need to eat still
) and if you feel sad and you need to cry, like beerab stated above, it is better to cry than eat.
Hang in there and don't give up on yourself. As guamvixen suggested, use this time as a motivator to improve yourself.