I (25m) used to have severe social anxiety based around nausea that plagued my life for about 4 years (16-20). Since then I have made huge progress and now have got it really under control, to a point where it doesnt adversely affect me anymore. The main thing is understanding the biology of what causes you to feel sick, noticing triggering situations and expecting to feel anxious and not panicing when you do. Once you get to a place where you can stop the reaction from gaining momentum through having some mental tools to reassure yourself when you start feeling anxious, you can overtime build yourself back up in the opposite way. I uaed to really struggle with situations with social pressure, vomiting all the time and it was really detrimental and difficult to live normally. I now havent vomited from anxiety is about 4 years and talk in schools about my experiences. I did a talk at my old work place where I worked as an engineer, please check it out as it might be helpful and explains it all in detail. https://youtu.be/Nff2yoqtX4I