First thing , the problem looks severe, you need to consult a doctor for this issue. May be sometimes, over the counter medicines may work, but for your situation it doesn't work. So, my advise is to consult a doctor for the best solution.
How long has this been going on? How do you know it's anxiety? Have you had this happen before and went to doctors and they didn't find anything and attributed it to anxiety? Anxiety can cause a lot of digestive problems, no doubt, but so can a lot of other things. You could have a virus, food poisoning, a bacterial infection of some other kind. No way to know if you don't see a doctor. Now, if it is anxiety, what are you doing to treat that? Are you seeing a psychologist? If your anxiety is coming a lot more than usual, did something happen to trigger that? I've had pretty bad anxiety for more years now than I can remember, and severe anxiety since a medication problem years ago, and I've had a lot of digestive problems from both that and the medication given to me to treat it, but I've never had anything like what you're describing and certainly not anything like that go on for a lengthy period of time. I'm just one person so that doesn't mean a lot, but if anxiety did this to a whole lot of people there would be a whole lot of anxious people suffering from malnutrition and we'd know about it. So the first thing you need to do is see a doctor and get some tests done. You need to rule out a physiological problem, because otherwise, how would you know what is going on? If it is anxiety doing this, you need to treat the outbreak you're having and tame it to a point it's not causing you to starve yourself. There are a lot of digestive remedies out there both pharmaceutical and natural and a lot of the natural ones work pretty well, but again, you're not eating at all. You're going all the time. Find out why for sure so you know what you're dealing with. Peace.