A clinical examination and work up is necessary for determining the correct cause of your symptoms. It is possible that you suffered a vasovagal syncope. Prolonged standing, stress, dehydration, low blood sugar
all can cause vasovagal syncope. Acute gastroenteritis, acute appendicitis, irritable bowel syndrome all can cause severe abdominal pain. It is best to consult a physician and get evaluated. A clinical examination and work up for above mentioned conditions will be helpful.