I don't think you have IBS, not with a fever and the burning. Plus, there are several good medications for IBS and your doctor should have prescribed one for you. I would find a different doctor. Have you learned how to deal with the panic attacks, if not I can tell you. I went thru a time when my stomach would burn when I drank wine, I quit and the pain went away. I'm sure that you have done some damage to your body having drank beer for this long, but without being able to take medication for anxiety, and the panic attacks, I doubt you'll stop. Having to care for your dying mother had to be very hard on you. Have you sought the help of a psychiatrist to help you cope with your anxiety? I know a lot of people (especially men) think their useless, but trust me, they can and do help. Have you tried antacids for the burning? Go to your your local pharmacy and talk to the pharmacist and just tell him you are experiencing a lot of heartburn, what over the counter medication would he recommend. Then find a new doctor, you don't run a fever with IBS, fever is a sign of your body fighting infection.
My GI doctor put me on Nexium 40mg two times a day and I take Xanax 1mg for the panic attacks. I have gone to a therapist and had bio-feedback for two years. I have learned to control the panic attacks to a point. I've have had agoraphobia for thirty years now. I saw another psychiatrist for that and he said, that I've had it for so long that its very hard to treat, I tried all the therapy and everything that they asked,but its still there. Its just not as bad as it was before. As far as Heartburn, I don't have any. I use to have it so bad that I use to throw up bile. I've had every test under the sun. I stopped drinking beer for five years and the first time I had two beers the pain and fever came right back. I've seen a number of doctors about it and they just scratch their heads. One doctor told me that anxiety could make me run a low grade fever. Its all so strange!
Do a search for "celiacs diseae" or "gluten intollerance." I think you may find some answers. Celiacs disease is where you are allergic to the protein called "gluten" which is found in wheat, barley and rye products....basically everything that beer is made of. Good luck.