Please read my blog on PCOS. Hope that helps.

Hello, Irregular periods is caused by hormonal imbalance (like prolactin, oestrogen, progesterone,), hypothyroidism, reproductive tract infections, PCOS, anemia,fibroids, stress etc and certain medications like antipsycotic, antidepressants , you need to be examined first to find the cause, don't worry all can be managed with medicines please consult a gynecologist.