If you are in the reproductive age group , pregnancy
with abortion should be ruled out. Other possibilities are appendicitis
, urinary tract
infection(if fever, vomiting are present).Or it could just be dysmenorrhoea(painful menstruation
) . I think it is important to visit a physician and get a complete blood picture and a urine routine& microscopy done along with other relevant investigations thought of by the doctor after assessing your complete history and examination.