Congrats! And good luck.
Ask for a scopolamine patch for nausea before surgery - works amazing.
For pain, ask for paracetamol in an IV 1000mg - also works great. If pain breaks through that they will give you a narcotic like dilaudid, but likely you won't need it. You will be incredibly thirsty and have a dry mouth from the surgery, ask for biotene swabs, ice chips if allowed.
Yes, you will mourn some food loss, and food volume - you will adjust and be fine. If not - seek counseling, seriously we all have food issues. But you WANT this surgery, NEED this surgery, and you will be successful - follow the surgeon's plan. Good luck.