If this started when you were on antibiotics, you're on the right track about probiotics but yogurt isn't the answer. While yogurt is an okay prebiotic, it's not much of a probiotic source, as the organisms used to culture it are killed off by pasteurization. Some of your better quality yogurts found in health foods stores put some back in, but not very many. The best thing you can do is go to your best local health food store and buy the best probiotic supplement they have in their refrigerated section. These have billions of organisms. You want one that has a good selection of organisms, but especially bifido bacteria, or bifidus, as it's very involved with digestion. Other good sources are cultured vegetables, such as kim chi or sauerkraut. Because dairy is often a problem in itself for humans, it's best to look elsewhere. It's not sodium -- I don't know where you got that idea -- but it could be a form of sodium found in many restaurant foods, especially Oriental, called MSG. And I'd also suggest you start to eat a healthy diet at all meals, at least for awhile -- all the restaurants you mention have cheap and therefore horrible food full of artificial ingredients that could pose a problem, and that breakfast of yours, well, I'm sure you know. You're just perpetuating your problem. As for your anxiety attached to this, that's a separate issue, and a therapist might be a good place to start to see why you've become so anxious about eating in general -- most people with an illness or drug-related problem (the antibiotics) don't become that anxious, they just get mad.