Was there any dressing on your lettuce/tomato? Did the chicken breast have skin on it?
Personally if a meal doesn't have enough fat for the amount of the other things it has (protein+carbs) ... if it's not BALANCED in a primal fatty way... I tend to also be snacky afterward even if I'm "full."
I don't think your body is still desiring simple sugars. You're just mis-reading the signals. Your body wants fat for energy and the few slices of bacon and the avocado just weren't enough.
That's my theory anyway. Next time have a chicken thigh with skin on it, and use lots of good EVOO on your lettuce and tomato (maybe with some lemon juice or balsamic vinegar too).