I am so bummed. I ordered a diet coke today for the first time in ages (didn't have any soda during my recent pregnancy). I was drinking it and enjoyng it so much. My DH took a sip and said "that's mine, it's regular coke.".....AAAARRRRGGGGGHHHH. I drank almost the whole thing. How far did i just set myself back????? I am so sad.

you don't set yourself back at all. You do delay when the date is that you'll reach goal, but that'll happen. This is a permanent way of eating, now, and you're getting there (to goal) as you are meant to get there.

It's okay to feel sad. It's also okay to give up diet coke and switch to water! That way, mistakes are unlikely and your health has a chance to recover from artificial sweetener use, as well.