This feeling of fluttering in the stomach may be due to peristaltic movements of the food in the intestines or due to muscle cramps of abdomen.
Frequent abdominal muscle cramps are seen in prolonged exercise,stress and anxiety,anemia,dehydration and deficiency of sodium, potassium, magnesium, and calcium and in serious disorders like myotonia,vascular disorders and neurodegenerative diseases.
Eat healthy nutritious food and keep yourself well hydrated.Also get your Hb levels evaluated for anemia.Usually,these symptoms go away on their own after a balanced diet,but if the symptoms persist then a clinical evaluation by a physician is desirable.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.