Oh Hayley, I am with you. I fall off constantly, The first time I read David's book I went 5 weeks no problem. Them Whammo. Next time it was 3 weeks, then 6 , then 6 again. The moment one little sugary thing goes in your mouth, the cravings are back like a wild animal.
Don't cut yourself up. Realise that you are not alone . We are sugar alcoholics and it is an addiction. The thing that gets me back fastest now is to realise how sluggish I feel when I eat sweet things and remember that great feeling of euphoria when I cut them out.
Trying re-reading David's Raisin Hell series on addiction. And also give yourself credit that you have made a start.
I keep some nuts at my desk, that helps. Winter is a tough time too, because I want to just stay inside and stay warm, but now that the warmer weather is here it is getting easier.
Keep going. Karen