What complications with a gastric sleeve could cause vomiting and nausea (worst in mornings) 10 and a half months post op?

It's been 10 and a half months since I had a gastric sleeve and I am still having nausea and vomiting with the mornings being the worst. I've had an endoscopy and the Doctor couldn't find anything. If I don't have something in my stomach, i start to get nauseous and I usually vomit foam. The pain feels like hunger pain but actually painful and can be debilitating in the mornings. I've tried every medication I could possibly try. Simethicone can reduce the foam. Ondansetron can reduce nausea.