Nausea is my ONLY SYMPTOM. Someone help!?

Had a bunch of tests. everything was fine. Ultrasound technician said I had a tiny kidney stone but that it was nothing to worry about. Had everything checked--everything. Been going on for 6 months on and off. Nausea starts around 3 or 4pm until around bedtime. (11:00) Nothing else is wrong. ONLY nausea. Not sure where to go from here. Had an endoscopy this past summer, gall bladder check, stool check, all of it. Why am I sick everyday after 3pm?