Believe it or not, your medical team likely expects you to have some problems with eating and drinking for the first few weeks. In the short term, it won't hurt you, but make sure you get those vitamins and minerals down. And Annie is right. Drink hot drinks like tea, and I personally don't see anything wrong with caffeinated drinks if you can keep them down. It's more important to drink than to eat. Even in a dire situation, a body can go longer without food than without water.
And if you're ambulatory, get up and walk short distances. If that makes you throw up, that's okay. You need the movement in order to activate peristalsis and prevent clots in your blood.
Some people breeze through this surgery, but they still have the same healing curve as you do. You've undergone a massive body change and you're in the healing phase, which takes as long as it takes. The more you put into it, the better it will be. Don't give up and don't give in to any craving that you think would make you feel better. Chances are, it won't.
Whether or not you made a mistake with this surgery will become evident over time. But right now, you're suspicious of the surgery, rather than all the other things that are fighting you. It's not easy to leave obesity behind and your body and mind and eating disorder will conspire against you and point their fingers at the surgery. You have a perfect right to feel insecure right now, but as time goes by, you'll be glad you did it.
Stay strong, have courage, say affirmations and cast out the demons that want to harm you. Do anything other than sitting or laying down and feeling depressed. That's what kills your spirit. Building spirit is just like being a bodybuilder. It comes over time, with repetition and fidelity. Try adjusting your inner voices and see what happens.
And know that we are here for you and many of us have survived and thrived over many years.