I had a gastric emptying test which showed fast movement. One GI said showed dumping syndrome and another said showed nothing abnormal. Capsule endoscopy showed the capsule stayed in stomach for 2.5hrs. One GI said showed gastrointestinal and the other said it’s not abnormal.

My 66 yo husband has just been diagnosed with Gastroparesis, after 10 months of the exact pain and symptoms you are describing down to the losing consciousness. He never threw up, but constant nausea, pain and no appetite. He has lost 40+# in 10 months, has no appetite or energy. We have been to the ER 4 times, had blood tests, xrays, cat scans, mri's, upper GI, colonoscopy, youname it, they all came back with no issues! Finally a Gastric Emptying test showed he has 25% still in his stomach after 4 hrs. He tried Marijuana but didn't like it, to CBD gummies help. Now that we know what he has, we are trying hard to get a handle on this. Following a strict Gastroparesis diet helps a lil bit at this time, he still has no energy, pain still persistent. We follow up with his new GI in 2 weeks., so hopefully he gets better soon. Like you he is at his wits end and isn't coping well with all this. He did find out he also has diverticulitis & had a severe case. We didn't even know he had any issues prior to this.
We are told it takes a while to heal. Just praying he has the strength to hang on, he is very depressed and says life is not worth living if it continues like this. I tell him he has to want to live to get better. He has to put the effort in, not just me doing all I can for him. Prayers you get answers and my husband heals.