Weight loss surgery doesn't cure your emotional ties to food. That's something you need to work on separately. I also think it's at the root of the problem. The WLS might help you to lose weight more easily but if you don't get the emotional part worked on then it won't guarantee that you'll lose weight or keep it off.
I think that people's weight level is more in their heads than in their stomachs.
You knew this was going to be difficult and I am sorry that you're expecting more difficulty than you thought you would but you have to be able to know that it's worth it and find pleasure in other ways besides food.