My period is five days late.

I have been pregnant before, so I know the symptoms. My breasts are no tender. I am exhausted, but I have been working 60+ hours a week.  I am late on my period, I took a test on the second day I was late and it came out negative. I can feel my period coming, but nothing is happening. 
*Disclaimer* 
The weeks leading up to my period, I have been stressing so much for work, bills, and money. I was nervous for a promotion I was up for. (Which I got) and I completely changed my schedule. (Been waking up earlier) I have a feeling all of that combined has made it late. But I am still worried since I did have unprotected sex about a month ago and my period are pretty regular.
What is up??