I've also had two friends that did the Gastric Bypass. The best advice...don't hop on that scale too often. Your body has been used to eating and receiving calories a certain way. It's going to fight to keep your weight because your body will naturally try to regulate itself. so don't sweat the scale too much. Instead focus on how your clothes are fitting you. I had my surgery in December and what I notice is that I'll drop weight and level off then it starts again. I visit my scale about every two weeks. I've dropped from a 26/28 to an 18/20 and I'm sure I'm about to dip further.
I love to cook and I love good food. I don't substitute the real stuff, such as sugar. But I will, when I can add tofu for Protein, rice paper for flour tortillas and sandwich thins by Oroweat for bread. And stay away from carbonated drinks, it took me a good two months before the carb and soda cravings stopped.
Good Luck