Heather - I am not a postop yet, but I can relate to how you're feeling. Once I was on "The Amazing Micro Diet" which was a liquid diet. I lasted only a week, because there was no way I could continue to not eat. I knew it was time to give up when, just to put something in my mouth, I opened a can of tuna (I am not a big tuna fan), forked through it, tapped off the tuna and just sucked on the little flakes that stayed on the fork.
I think before you eat something, if you can make it through to Monday, call your doc or nutritionist and get their advice on a reasonable step.
Either way, you will see the reward of your dedication in a month or two. I don't know if gum is allowed, but if it is, I'd sure be chewing it!