Could Delayed Periods With Negative Result In HPT Indicate Pregnancy?

Hi. I am currently 16 days late for my period and with 2 negative pregnancy tests I'm worried. My periods are normally on time, they are never late. The first day of my last period was the 26th November 2014. I don't my first test on the 3rd jan and the second one today (7th jan) I'm getting slight early signs of pregnancy but not completely sure. Is there a reason? Could I be pregnant? Please help.