If you were having regular 28-30 day cycles in the past, then this absence of bleeding for so long is definitely abnormal. You should get investigated for this amenorrhoea. As your home pregnancy
tests are negative, you should go for the blood tests and a trans-vaginal sonogram. If you are not pregnant, other causes like hormonal
imbalances, sudden changes in weight, life style and infections or medications should be excluded.Please see a gynecologist for a proper management. Good luck.