Here is the tough pill. If you did good all week, and are bad every Sunday night then that is your average. Your Monday weigh ins should still show loss from the week before. If they don't, then you either didn't do good enough all week or you went too hard at the buffet Sunday. Even if you went too hard at the feed trough one week for Sunday, it might screw up one Monday, but the following Monday would show the correction. It doesn't matter if Tuesday or Wednesday are lower than Monday. It matters that each day is lower than that day the week before. If you want to have the bar food on Sunday then you need to do even better Monday through Saturday. It is the weeks worth of calories in vs calories out that maters.
In simple terms if every Monday is 220 and you don't like that number, but you like seeing Wednesday at 215 then you shouldn't be happy until you see Wednesday at 212, then 210, ect. If you do that then Monday should also go 218, 216, ect.
Monday is just easiest for me to remember as it is my first early morning I have to get up for work. The rest of the week is going through paces. I can adjust mine if everyone thinks they would get them in better on another day.