Your stomach bugs must be because to the some bad items or agent in you shake. So it is always advised to maintain a very healthy and nutritional diet plan after the surgery that will help you gain a quick weight loss without any side effects. I was in the same situation few months before then Lap Band Surgery Book helped me a lot more information about the prevention, precautions, diet plans etc of the surgery. You will get more information about the software from : http://www.lapbandsolutionbook.com/lap-band-meal-planner-book.php