Oh oafette... Don't beat yourself up over one piece of pizza ! I did struggle with upset tummy in the first couple of weeks , terrible cramps and the trots in fact I started a thread with the exact title - upset tummy!
This is a HARD diet and way to lose weight I don't care what anyone says .... We all have a problem with food, that's why we're all fat! So to not eat at all is going to test us and some of us will blip at times but we can do this is we stick together. Not liking the exante packs is going to make it doubly hard for you too! I managed to get thru the first 4 weeks with the bumper pack, now I just have the choc orange bars and choc shakes, slightly more expensive but it's the only ones I can really tolerate .
Draw a line under your piece of pizza- look at your lovely husband and kids and think to yourself "I CAN DO THIS" and jump right back on the wagon tomorrow. You're not the first person to have slightly gone off plan and you certainly won't be the last ( I almost joined you today).
Best of luck and keep posting.
Keep those chins up my lovely ;-)
FB xxx