Nauseous and dizzy after eating at restaurants

Im a 23 year old Female, about 160 and 5’6. I’m on birth control and Pristiq. I’m at a loss and could really use advice. The past 2-3 years I will randomly get super nauseous and dizzy and feel like I’m going to faint after eating at a restaurant. It never has happened at home. It feels very random and I can never predict when it will happen. I can eat the same thing at home, super carb-heavy and will feel nothing wrong. I’ve always had anxiety, treated, but I’ve never thought I’d be anxious eating at a restaurant. I typically have to leave the restaurant and walk and then I’ll feel better. My regular blood tests are normal, I’ve gotten an endoscopy and colonoscopy. I was diagnosed with Barrett’s esophagus (not severe) but the specialist never said anything about GERD. I’m considering going to a holistic doctor because I’m desperate and love to eat at restaurants! Any advice is appreciated!