Pregnant

I recently found out I am pregnant. I was on depo shot for 6 months, and then it took me another 12 months to get pregnant
I kept getting negative pregnancy tests after my missed period until it was 2 weeks late. 
Is this normal ?
Cause I thought you get a pos test the day of or a few days after missed AF. Not 2 weeks..
I confirmed with blood test at my doctors the other day