First off, why have weekly cheat day? If that keeps you from eating junk the rest of the week, then by all means, keep doing it, but if you can live without it, you'll be better off. I used to do the same thing -- I would go out and have a big piece of cheesecake almost weekly. Now, I do that maybe once or twice a month at most.
I've also just recently started fasting. Make sure you're eating enough food when you do eat. I fast on workout days, and after I work out, I'll have an "eating window" where I eat 3,000 - 3,500 calories.
Keep yourself busy and drink plenty of water. Try to do something slightly active -- go for a walk or go run errands. You might find that you have more energy for it when you fast!