I remember having exactly this tearful reaction about two and a half weeks in, on Kings Cross station of all places. Previously if i was waiting for a train i took it as an excuse to have a sneaky pasty or something. And I couldn't. And I felt so deprived, like a child whose been told everyone else gets ice cream except for them. I was passionately, furiously upset - although i counldn't articulate the full extent of it or my husband would have thought i was totally insane. I wasn't hungry, the pasty wouldn't have been especially nice, but i was getting into a proper state.
And what I eventually realised, some weeks later, is a couple of things: firstly, I hadn't stopped myself having whatever food i wanted for a very long time; and secondly, i had lost the ability to be sad without tranquilising myself with food.
Overeaters tend not to be very good at the whole 'delayed gratification' thing, and we respond particularly strongly to seeing a food and then thiinking that because we fancy it, we need and deserve to have it. That's a tough one to break, but one of the few things that i think cambridge abstinence might be able to break the habit of, if we're watchful.
The other issue is bigger and harder though. Addicts of all kinds are prone to use food or drugs or booze or shopping or betting... to take away feelings they don't like. And learning to sit with your sadness, to accept that sometimes you will feel sad and hard done by, and deprived (or stressed, or put-upon, or angry...) and that you are an adult and sometimes adults have to feel that way - everyone does - and that experiencing those feelings is part of life and will NOT kill us... those are really tough changes to make.
most of us have abused food to take away feelings since we were young - and what we need to do, what this diet is forcing us to do, is grow up overnight. which is why sometimes we react like a seven year old on Kings Cross station because we can't have a greasy cheese and onion slice from The Upper Crust.
It gets easier. Obviously I still fancy thiongs I can't have, because all i can have is my packs, and they're not especially yummy... but i haven't cried about food since august. which has GOT to be a victory.