Anxiety Support Group
Anxiety is a physical condition marked by intense and persistent feelings of distress, fear, angst or dread. General anxiety caused by routine day-to-day stresses usually passes quickly and is experienced by almost everyone at one time or another. However, such feelings that linger over time and are very difficult to cope with, and which lack a clear cause, may indicate...

Anxiety can cause so many symptoms...but everyone may not experience the same symptoms. Nausea and the others that you mentioned can definitely be a symptom on anxiety. I get a loss of appetite among many other symptoms when my anxiety kicks in. The symptoms usually don't last, once you get your anxiety under control the symptoms will go away.
Just a theory. . .
When my anxiety is high it definitely suppresses my appetite and the thought of eating can make me feel nauseous. I typically lose some weight and have to drink ensure and eat bland food while I try to get back to a calmer place.