Hormonal imbalance, stress, certain medications as contraceptives, polycystic ovarian syndrome, eating
disorders, vigorous exercise and thyroid
disorders, could also cause delayed
period. You can do a urine pregnancy test, and if it is negative consult a gynecologist.
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.