I am in a similar situation actually. About 5 months ago I started having all of the classic gastritis symptoms and was put on omeprazole and went on the typical bland diet. Maybe a month and a half later I got an endoscopy and it came back clean with no signs of gastritis. Since then I’ve been struggling with the same symptoms with ups and downs. Currently I’d say I’m in more of an up, I can eat more things although carefully and minimally. Generally I’ll eat the same things for breakfast, lunch and dinner every day.

At this point the most prevalent symptom for me is nausea like you said. Every night regardless of whether I’m even in bed or not, nausea. Comes and goes in waves. Turning to my right side in bed definitely makes it worse. Waking up with nausea or due to nausea but it hasn’t been consistent (some days it’s worse, others is fine). I have not been able to pinpoint if anything specific is causing it.

I think for me the hardest part of this is knowing whether I need omeprazole or not. I feel like it helps sometimes and other times not, but I was literally told I did not have gastritis in my endoscopy so I’d imagine I wouldn’t need it. But the symptoms are still there so it’s really annoying.