Well, regarding the food, I will tell you that I have had weekends that were less than stellar as far as quality of food goes and of course they were also high quantity as well. And my weekends are 3 days! And they have not derailed me. As long as you don't let guilt cloud your thoughts, and you have planned for the day. You will do well. Note that most people, even those who have done real fasts in the past, have trouble with either the first few, or they do well to start then suddenly for no apparent reason have a few about a month in that get hard. Just keep working it and it will work for you.
Today is a down day for me as well. Dinner tonight...lovely cod fillet and a huge salad.