It's Not Just in Your Head — These Are the Physical Symptoms of Anxiety

If your anxiety is bad enough, the butterflies in your stomach could lead to full-on GI issues, such as irritable bowel syndrome (IBS) with diarrhea and/or constipation, Dr. Cassmassi said.

"Serotonin is the neurochemical that controls both gut activity as well as mood and anxiety, so the reduced serotonin in chronic anxiety states also can wreak havoc on the gut," Dr. Cassmassi explained.