That all sounds very familiar to me. The worst part was the weeks of not knowing what was wrong with me, until the dr diagnosed anxiety, put me on anti depressants, and here I am nearly 7 weeks later and all my stomach issues have almost cleared up and I'm happy again. I had the same, burning stomach, and feeling sick all day, along with diarrhoea and lack of appetite. I've been signed off work for 10 weeks aswell while the tablets do their work, which thankfully they are. I also don't know the cause, is it anxiety causing the stomach upsets, or the stomach upsets causing the anxiety? Either way, I'm on citalopram and they are curing me. I also had the feelings of impending doom, and the worst feeling of all was that I was so sure I was stuck feeling like that forever.
My suggestion based on what you've said, sounding very similar to my situation, is try not to think of it as something that's physically wrong with you. Your stomach may well not be damaged. Treat the anxiety and that may well treat your stomach. For months I was convinced there was something wrong physically with my stomach. I simply wouldn't believe that my mind could causing this. But now here I am after a treatment of anti anxiety pills, and I'm better. One of he biggest steps too is accepting it could be anxiety causing all the problems, once you accept that and battle that, instead of trying to battle the physical symptoms, the healing will be quicker. If all your tests for gastritis have been negative and they can't physically find anything wrong with you, I'd bet my bottom dollar a course of anti depressants and some rest will sort you. It's a slow process, it's taken me 2 months to get here. But it is so worth it.
Hope this helps and things get better, i know more than anyone how hard stomach issues can be, especially when undiagnosed. I was absolutely convinced I had gastritis, and ulcers, or inflammation of the stomach lining, I was 100% sure. I'm as amazed as anyone that this can be caused by anxiety. And I was REALLY ill for weeks.
I actually just became a member today only to get help for my stomach pain. I got a severe stomach pain after a stressful month and after that I am on Ranitidine for more than 3 months now. Pain goes away and comes back. Any test done showed a negative response. One doctor says its just gastritis and one another says the next step is endoscopy, which I don't want to do. I believe this is totally related to my stress. This writing that taking citalopram helped healing gastritis and stomach pain, gave me a lot of hope. I'm in a constant stress due to my school and I think that doesn't let my stomach to heal completely. I was wondering if your stomach issue is completely gone and also if your GI doctor diagnosed you? Not knowing what is going on with me makes me even more stressed and I just want to feel normal again. I would really appreciate if you can help me with your response.