@socalfriend Welcome to Mayo Clinic Connect. I certainly hope we can help you! The nausea must really interfere with your total life. Have you lost weight? I honestly can’t tell you what is wrong but I will check out the Digestive Support group to see what i can find. In the meantime, lets wait for other members to comment. But, you might also check out the discussions on Hashimoto’s Disease.
https://connect.mayoclinic.org/discussion/chronic-nausea-for-6-years-help/
I checked out the Digestive Health group and they may have lots of answers for you.
Will you return and let me know if you get any hints? Did a rheumatologist diagnose the Hashimoto’s?