Unexplained digestive and GERD issues??

On June 21st, 2010, I was completely normal and felt perfectly healthy.  I ate a sandwich from a popular food chain that day, and I never got rid of the "too full" feeling.  I developed a feeling of a trapped air bubble under my rib that night, and the next day I started choking on acid reflux and started having acid/bile diarrhea.  The annoying air bubble feeling changed to pain.  My doctor placed me on prevacid twice a day to control the acid, but I know that is a symptom, not a cause.  He did bloodwork to check for H. Pylori and I'm not sure what else, but it was normal.  I had an abdominal CT...also normal.  I turned in a stool sample checking for parasites and food poisoning..normal.  I had an endoscopy/colonoscopy and aside from a small polyp in my colon that was removed, it was also normal.  BUT, I am feeling anything but normal?  What are we missing here?  I have a job with excellent health coverage...what do I need to do next?  I have felt so terrible at times that I am tempted to go to the hospital and make them admit me until they find it.  It is really starting to effect my mood and I feel depressed and anxious.  I have upper left quadrant pain in my abdomen which has now also started in my upper back in the same area...around the lower part of my ribs.  I tried to taper off the prevacid and the acid/bile diarrhea came back with a vengance.  I cannot eat anything without it coming up through my throat, and I feel constantly full....completely stuffed, but starved.  I just don't know what to do next.  I am going to see a gastroenterologist on Thursday and am hoping for some answers.  Any ideas of what to look for?  Or what we're missing so far?  Is it possible that this is some strange stomach virus that I need a specific treatment for??  I am at my wits end.  Thank you.