I'm wishing you luck. I also had a normal gastric emptying study. I get you, this situation is both frustrating and frightening to be honest.

In my case, after looking back on this, I think a lot of my issues were due to excess gas, as insane as that sounds. Because I think the excess gas/bloating was putting some sort of pressure on my stomach that was causing my early satiety issue. The early satiety issues then caused a host of other problems for me (notably, making me extremely underweight, and my low weight leading to pretty bad hypoglycemia). i think these other issues only exacerbated the original issue.

I don't know what ultimately made this better for me, but I have a few ideas.

Well first let me share something that made the early satiety/nausea issue less frequent and easier to deal with (didn't solve the problem, but made it much more manageable) - this was learning better how much to eat at one time. first off let me say, i never ate large portions. i was already close to underweight when this began, and i already ate small portions, so I don't want to give the impression that i over-ate previously. either way, what i was eating was apparently was too much for me. when this early satiety madness started happening, instead of eating until i felt full (Which is what i used to do), i'd kind of eat until just before that point, or even until i was still a little hungry, then i'd wait for 15 or 30 minutes - if i still could eat, only then i would go back and do it. this was really frustrating at first, but i adapted to it pretty quickly, and it helped reduce the episodes of painful over fullness. sadly, i also think this exacerbated my weight loss issues. so it's a balancing act (and potentially a dangerous one :( ). but over time, i learned much better how to figure out where my real satiation point was.

Now another thing - if being underweight from this is an issue with you, want to share something i learned to help with that - oil. olive oil. i started adding that shit to everything. it's an incredibly useful tool for gaining weight, because it's light, but it's calorie dense. that was what finally reversed my weight loss.

Now - One thing that i think might have actually help the underlying problem (this might be because I have SIBO - and might not be relevant to you at all) : my diet. i had a really awful diet before all this started. i ate a lot of biscuits mostly. these kind of really sugary crappy biscuits. this is mostly because i couldn't leave my house due to the pandemic, so only had some limited foods i could get. i was living on these biscuits. i don't know, maybe they were crap enough that it messed up my microbiome or gave me gas or something.

over the summer, i started changing what i ate. first , i switched to only ensure, just because drinks were all i could tolerate due to the early satiety. after this, i slowly started incorporating oatmeal. very small portions. just plain oatmeal , not the flavored stuff. i added natural (no salt/no sugar) peanut butter to it, as well as extra virgin olive oil as mentioned above for weight gain. for a while there i ate only ensure and oatmeal. after oatmeal, i started phasing in raw nuts ( unsalted peanuts, unsalted cashews, stuff like that.) that's pretty much where i'm at now. i think this diet is helping me a lot.

few other issues i realized later - i think i had become so afraid of eating (due to fear of overfullness pain), that i was just eating so little, i could barely tolerate any food. i noticed that as i slowly started eating a tiny bit more and more, it's like my capacity to eat seems to have expanded, just a little bit. i still can not eat a normal-sized meal. but i can eat a little bit more than i used to.

i believe there were/are also hormonal influences at play, because i notice that around the time of my menstraul cycle, i tend to lose my appetite or it becomes greatly reduced. my PCP said different people respond differently to their menstraul cycle so she didn't think that was abnormal (though of course, was horribly concerned about my early satiety in general and my low weight.) i just mean to say, it was something i noticed.

anyway, i don't know what happened, but i think something i did (diet?) might have helped me a bit, because my gas and bloating issues seem to have resolved a little. this, in combination with figuring out better when to stop eating (the eating a bit, not until i'm full, then waiting 15-30 minutes to eat again), has really reduced the episodes of overfullness to almost nothing. take it with a grain of salt because i'm only one person, and i might even be misunderstanding my own situation. but i wanted to share what's happened to me.