I had a similar swallowing problem for a year and a half when I was in my early twenties. It was some sort of hysterical dyphagia (sp?), I felt like a had a giant lump in my throat all the time. It turned out that it was due to anxiety. All I could swallow was mushy cheerios, I lost about 10 pounds very rapidly before they put me on an antidepressant/antianxiety med. It took me about a year of progressive muscle relaxation training and doing the muscle relaxation every day to get rid of it. I still have a very strong gag reflex.
Go to a heatlh food store and see if you can find a vegan, gluten free protein powder. Perhaps you can mix that with water and get some protein that way. Also, ghee is a good way to get calories and there is no lactose in it. You could soak something in melted ghee to get calories.
Also, has your doctor checked for any obstructions in your esophagus? They need to rule that out first. Also, they should check to make sure that you have no erosion in your esophagus if you do indeed have GERD. Also, something to consider with antacid medication is, in time, they actually make your stomach more acidic. They can also block your iron absorption.
I would recommend, with a doctor or naturopath supervision, starting a probiotic and a liver detox, maybe the molybdenum since you can’t do milk thistle.
Good luck sweetie, sounds like you have had a very hard time.