It is possible that you could have an ulcer, or another kind of irritation in your digestive tract, from taking one or more of those meds, and anxiety could make something like that worse. Some meds can also cause acid reflux, which can cause stomach pain and nausea.

If you are still suffering, you may want to try taking an OTC like Prilosec (if there are no interactions, etc) for a little while to see if you experience any improvement