Hello I share your concern Looking at your history this could be due to Acid peptic disease due to stomach hyperacidity, signs of imminent periods or colitis I would like further information to help you better is it associated with stomach fullness, vomiting or bloating your last periods and normal duration of the cycle? History of unprotected see? I would advise you following guidelines Say no to smoke and liquor Avoid fatty fried spicy and junk food or carbonated drinks Have lots of fresh fruits and vegetables Just relax and enjoy your life you can take antacids medicines along with antispasmodic drug. if it s persists than consult your doctor for examination and blood tests and urine tests or an endoscopy if need be. Best wishes