Maybe anxiety. I remember my earliest symptoms after having my massive panic a few weeks ago was my heart constantly pounding and horrible stomach issues. I couldn't breathe at times, I'd burp every few minutes, I would get nausea after eating, I had no appetite, my bowel movements changed, I had pains and pressures all around my chest and abdomen.. I began worrying I had colon cancer.
My doctor prescribed me Zantac and my gas disappeared within a few days. It might be IBS brought on my stress.