I am so sorry that you are not feeling well!. I agree with everything that Nanners has suggested. I would get another opinion from a GI doctor. I want to encourage you to keep at it until you feel like you are being listened to.
Before I was finally diagnosed I had gone to three different doctors. They all thought that I was anorexic and just had a nervous stomach. I can't even tell you how many antacids they had me try. One doctor even thought that I was lying to him about being pregnant. He was sure that my side pain was an ectopic pregnancy. After I finally told him that unless Jesus was coming back again through me NO I am not pregant. He then dropped it:)
Don't give up! I am sorry that you have to fight so hard for this.