If you were regular with your cycles previously, this period of amenorrhoea is definitely abnormal. With repeated negative pregnancy
tests the chances of pregnancy are little. Yet, you should exclude pregnancy through a blood test
and a trans-vaginal sonogram would give you complete information about any pelvic cause. You should get a complete hormonal
profile, blood counts and urinalysis
, if pregnancy is ruled out. Weight disturbances and stress may also lead to such changes; maintain a healthy body weight and do some regular exercise. Good luck.