Mmh, I'm sorry you are going through this.
I haven't had the surgery yet so I can't give you any reason. It just doesn't seem right tough.
Have you been back to your surgeon? It sounds as if you need to see them and have your concerns addressed.
If you can eat anything and everything....you haven't failed, the surgery has. That is what the surgery is meant to prevent. You wouldn't have needed the surgery if you could control your eating habits without help.
I repeat.....it's not your fault! Maybe a dietitian can answer some of your concerns if you can't get to see your surgeon.