I used to suffer from it big time. The least bit of stress could set it off and it would last for days. It was diagnosed as various stomach bugs for years and treated with antibiotics and such, then finally the doc said it was "severe nervous stomach" along with IBS, etc., and she gave me a prescription to take for nausea, but it didn't help. I can't remember the name, but for some reason I'm thinking it might have started with a p.
Fresh ginger slices under my tongue ended up helping ease the nausea better than the prescription ever helped. Also, sipping on fresh ginger "tea" or real ginger ale...not the ones sold as soda that don't actually have any real ginger in them. She also gave me xanax for the anxiety, and ambien for insomnia, as she felt that was causing all the rest of the stuff, although a sleep study determined I had no sleep issues. lol I guess the meds helped somewhat, at first, as it usually knocked me out or made me too tired/lethargic to do much else, although it never really addressed any of the actual issues causing the symptoms and the increasing side effects of all that stuff were overwhelming me in many ways.
Years later, after finally leaving a highly stressful job, having the full-time step-kids grown and gone, having relocated from a concrete jungle to a serene nature scene, still having my supportive hubby hanging in here with me, luckily having acquired skills that I never knew I even needed to add to my therapeutic tool box, like breathing exercises, fun daily movement, unlearning what had been repeatedly drilled into my brain for years, and making overnight drastic diet/consumption habit changes, thanks to a medical emergency, I no longer suffer from nausea, along with a few other things I'd been told I'd just have to get used to and would need meds for the rest of my life to manage. I had to totally change life as I knew it just to be able to get through it, pretty much. Hope you can soon find some lasting relief.