the omeprazole should work at this point, so i don’t personally think it is GERD. when i used omeprazole it helped by the next day for my GERD and reflux issues, but not my nausea and stomach pain. i would look into gastric emptying disorders. i was told that the extremes of an empty stomach or too full of the stomach can cause pain in individuals who have it, and it’s the same for me (self diagnosed and currently on that diagnostic path with professionals for this!). here is advice i had gotten from my gi doctor and nutritionist about issues is gastric emptying: what helps the most is eating small meals frequently that are high in protein and low in fat to help your body continue digestion. it’s also better to generally eat foods that are easier to digest and chew your food well. in general, letting your stomach get empty for a long period of time will make the pain worse when you end up actually eating, because your stomach may be delaying digestion.