Hello, There are several reason of missed period (besides pregnancy) like Ovarian Cyst/ PCOD, hormonal imbalance, over wt/ extreme loss, mental stress, emotional upset, eating disorder, thyroid problem etc. You may require one USG lower abdomen and hormone test to confirm the diagnosis. Then you must consult with your gynecologist and take advice according to test reports. Combined hormonal pill may be given to induce and regularize period. Control body wt by regular exercise, avoid stress, take healthy low carbohydrate diet and sleep properly.