unexplained nausea!!

Ok, someone please help me! I've been nauseous for about 8 years now. I had an upper gi done 8 years ago that showed acid reflux. my acid reflux meds do not help, they never have. No matter what kind they prescribe me. I was given an upper gi again a couple months ago & the acid reflux didn't even show up. I am nauseous randomly, day & nite, after eating & before. I've cut out most everything that is spicy, greasy, fatty, rich, dairy, etc & that has helped with the frequency of the nausea but it still occurs. Usually I can link it to something I ate, but not always. It wakes me up during the night. I don't vomit, but only because I have a fear of vomiting. It seems to occur frequently before bowel movements & is sometimes relieved after wards. I've been on phenergan for 8 years & zofran for 3 & I hate having to rely on medication all the time--the medications have actually stopped working anyway but I take them when it gets really bad hoping it will help some. Please help me!