soreness has gone down but the nausea continues?

A month and a half ago I had a sudden bout of gastritis that began as a feeling of nausea as I sat at work. Dismissing it as anxiety I took a day off and returned to work only to find that I was having the same feeling. I also began to fill sore ribs and a sore belly as if I had done a million sit-ups. I also noticed that my symptoms were made much worse
by sitting or any type of pressure to the abdominal area. The doctor put me on Prilosec and, although it helped with the nausea, I began having trouble breathing. A call to 911 showed that nothing was wrong although it was difficult to catch my breath as I spoke. After a EGD, it revealed that my stomach and esophagus were in fact irritated. I began to take Tagamet, only to experience the same breathing issues. The doctor has shed no light on the problem nor has she explained the sore ribs. I also had some upper back pain with this issue. Some of the physical soreness has gone down over time but the nausea continues.