The digestive system is extremely sensitive to stress...blood is diverted away from it and redirected towards the heart and large muscles of the arms and legs as part of the flight-or-fight response. This is an adaptive response in acute situations...being chased by a tiger...but it becomes quite detrimental to your health when stress is chronic since energy and nutrients are also diverted from the digestive system. Digestion becomes compromised and digestive functioning declines.
Read up on cleanses and dietary suggestions on this site...particularly colon cleansing. Also take steps to reduce and manage stress... meditation, deep breathing, exercise, etc. Castor oil packs can help to relax your abdomen and break up any congestion. You may also want to explore why you'd become so anxious about your stomach growling...perhaps there are some deeper issues here...like a fear of drawing attention to yourself? You don't need to hide...or give up your education or dreams!
If you have more questions...post them on the most recent forum...we'll be glad to help you!