Sparkling, plain water is allowed. If it was fruit flavoured, then it will have had sugar in it. I'm vegetarian so don't know anything about meat and Cambridge (or meat by itself!) but chicken and lettuce are, I believe, both allowable in the 200-calorie meal list, so look it as an SS+ day, even if you were slightly over the allowance. I'm sure your ketosis won't be badly affected, if at all. Have your products though, if you can manage it, so that you get all your vitamins and minerals and fibre for the day.