Since you have a delayed period with repeated negative pregnancy
tests, your doctor will try to establish the presence or absence of a pregnancy through a physical evaluation and a trans-vaginal sonogram; blood test
for estimation of serum beta-hCG
titres, coupled with these, is always helpful. If pregnancy is excluded by all these means, it remains to be seen if there is any hormonal
imbalance that could have caused this delay through further investigations. Finally, you may be suggested some form or hormones to induce a period or treat any imbalances. Hope this helps.