Hi Mike! Congrats on your commitment and I feel sure that you CAN do this. I really identify to your croissant slip-up. I lapse into the same way of thinking when I'm doing well, and think that just a bit of sugar (or even artificial sweetener) won't hurt me, and then that's the start of a really slippery slope - I essentially undo my progress and it takes me a few days to get back on track. So I've come to realize that sugar (or refined carbs) are seriously addictive and that thinking I can treat myself every once in a while is like an alcoholic thinking he can have "just one drink" every Friday night.
Anyway, wishing you luck! I do believe that we can conquer the demons...
"If it is important to you, you will find a way. If not, you'll find an excuse."