Once the end is in sight, its hard not to start questioning your decision. Honestly, I thought about leaving the hospital, right up to the point when they injected the drugs lol Change is scary AF!! Especially when its truly a life altering, forever change. No wonder you're questioning yourself. It is natural, very common and you'll be fine .. Seriously.
You CAN be successful at this. You absolutely CAN have a sane food life. I will be 4 years post op in June. I'm still under my goal weight (although, not at my lowest weight. But that was expected), I still get to enjoy food, coffee and occasional desserts. And I cannot stress this enough .. I feel A M A Z I N G !!! At 53, I feel better than I have felt in decades. Yes, multiple decades with an S.
You're doing one of the best things you can do for your long-term health and quality of life. I have zero regrets and would make the same decision again and again.