There is nothing embarrassing about this issue being presented to your physician, since it can indicate a certain gastrointestinal disease.
This stomach growling, or rumbling, can result form incomplete digestion of certain types of food, like carbohydrate-containing foods including milk and other dairy products ( condition known as lactose intolerance), foods containing gluten, protein in wheat, barley, and rye (celiac disease), or incomplete digestion of fruits, vegetables, beans, legumes, and high-fiber whole grains.
Since you have noticed that stress makes it worse, it is very possible that this symptom is a part of IBS (IBS episode can be provoked or made worse with stress and anxiety).
Another reason for this frequent bowel noises is carcinoid tumor (it is accompanied with diarrhea, hot flashes of the neck and upper chest).
For the right diagnosis and treatment visit a gastroeneterologist!
Best wishes!
Marija