Chronic Nausea, Diagnosed With Food Allergies, Nausea No Better, Told To Try Nexium. Could It Be Gallstones ?

I ve had chronic nausea for 15 years now (I m 32) but it s grown worse over the past few months. I was diagnosed with food allergies but, after 3 1/2 months of avoiding all of those foods (it s a long list) the nausea isn t any better. I went to a gastroenterologist who did an upper endoscopy and biopsies but everything came back clear - though, he said there was definite inflammation and diagnosed me with gastritis . He told be to try Nexium but it just made it worse and then he told me there was nothing else he could do. Over the past couple days I ve been having a lot of pain in the upper, center part of my stomach - bad pain (not sharp, though). Could this be gallstones or something like that? The gastroenterologist said he didn t think it was my gallbladder because usually when I eat it makes the nausea better. I need help! No one seems willing to help me figure this out.