When periods are irregular, one should get hemoglobin
,thyroid profile, hormonal profile( serum LH serum FSH, DHEAS, testosterone
, prolactin, serum insulin) along with pelvic ultrasound done. As you have mentioned that you are having multiple cysts
in your ovary, you could be having what is known as polycystic ovary disease which can lead to irregular menstrual cycle. Initiating a course of oral contraceptive pills
would help. For the same consult a gynaecologist.