Always nauseated. Done at this point.

I (35F from South America, not pregnant and infertile) have been nauseous 80% of the time since August 2021. Around the same time, I completely lost all my stamina. I used to do kickboxing and lift weights 3x/week, but now I get tired just washing the dishes. Not just normal tired, I get orthostatic hypotension, shortness of breath and really bad cramps in my lower back. I've had numerous tests done, all of which have come back normal:

- ECG & Echocardiogram (ruled out any heart issues)
- Tilt test (ruled out dysautonomia)
- Polysomnography (ruled out sleep apnea)
- Complete blood panel every 6 months (vitamin D and iron are normal, I have hypothyroidism but it's under control and results have always been within the normal range for over 4 years) - the only abnormality has been high cholesterol. When all this started, I was a vegetarian. Now I almost don't eat at all but I'm still overweight (1.65m/5'4" and 72kg/158lb).

A few months ago, I had an endoscopy that showed my stomach was full after 12 hours of fasting. The gastroenterologist suspected gastroparesis, prescribed mosapride (that brough no relief) and ordered a gastric emptying test, which was normal. He asked me to repeat the endoscopy, noting that I should " fast correctly this time" (meaning he didn't believe I had fasted properly the first time). The second endoscopy was normal: no gastritis, H. Pylori, nothing. But my life is shit. I'm nauseous all the time, I have no energy for anything, and I spend way too many hours in bed just breathing it out. I also get constant cramps in my neck and back, my upper arms and lower legs. I can be doing anything, having eaten anything (or nothing at all), and I still feel nauseous and exhausted. Having treatment-resistant depression doesn't help, and several doctors have easily dismissed my symptoms as side effects of antidepressants or just anxiety, even though I've been on several different medications over the last 3+ years. So, am I supposed to just learn to live like this, feeling worse than being french kissed by your grandfather? Nothing (natural or not) relieves my nausea except the occasional ondansetron injection, and that's not always possible. I haven't vomited today because my stomach is still empty after yesterday afternoon I had to hastily get off a cab to throw up my whole lunch on a sidewalk. I'm tired and no doctor has been able to give me any solutions or encouragement. Does anyone have any ideas? I'm not very hopeful that I'll get any replies (I usually don't) but I'm at my wit's end. Thank you in advance.