I had a blood test two months ago. I went through two sets of antibiotics and I am still having he symptoms. I went to a GI specialist and had a endoscopy procedure done. They didn’t see any ulcers. Also they checked my gallbladder and didn’t find any problems. What could this be ? My symptoms include : burning sensation in lower abdomen, severe cramps, I have been depressed, tired, loss of appetite and weight loss.