I think there are a couple specific SparkTeams for people who have had lap band & gastric bypass surgeries. Those teams might have some resources that will help you out!
I would keep following your doctor's and nutritionist's advice. If you are having trouble implementing their recommendations, go back to them and get a more specific plan.
I know one person who had surgery for weight loss (not sure what type), and it really worked well for her. It took some time and patience, though, and I know it wasn't easy for her to change her diet. But five (six? maybe longer!) years later she's kept it off & has never been happier. Good luck!
My Sparkpage is set to private, but I'm open to SparkMail!
"People often say that motivation doesn't last. Well, neither does bathing--that's why we recommend it daily." - Zig Ziglar