Hello, First of all, you should undergo one home pregnancy test at the earliest to rule out pregnancy and clear confusion. In absence of pregnancy, there are several reason of missed period 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. Progesterone pill may be given to induce period. Control body wt by regular exercise, avoid stress, take healthy diet and sleep properly.