I have been suffering from " IBS " for probably 15 years now. I have never had an issue with vomitting, even though on bad days I feel like I could easily do so. I also suffer from the bloating from time to time. It has gotten to the point where I where the next size up pants and cant buttong the top button due to the discomfort it causes.
You mention that you are taking medication? You may want to ask your doctor about side effects. That mixed with your IBS symptoms could be causing the upset tummy and vomitting.
Wish I could be of more help, but just thought I would share that does not sound normal, or at least not with what I have experienced.