My Period Is About A Week And A Half Late.

My period is about a week and a half late. I assumed I was pregnant, therefore I took a pregnancy test the third day of my missed period which was negative. I assumed I took the test too early so two days later I took another which was also negative. 8th days of my missed period I had some light bleeding. Which lasted about an hour or two then stop. I'm confused, am I pregnant or not? I have been having high levels of stress also if that means anything.