Don't freak out....it probably won't affect you too much.
Just make sure to keep your carb count as low as possible and you should be fine.
One time while on Phase 1, I went to donate blood (bad idea on 900 calories/day, by the way...but I didn't even think about it) and had a vanilla peanut bar so that I'd have something in my stomach. Well, after I was done and went to leave, I passed out. They wouldn't let me leave until I drank a whole juice box! I didn't even want to know how many carbs/sugars were in that. But I kept my veggie carbs and packet carbs really low for the next few days, and I was fine at WI.