Yes. When I was pregnant with my first child I missed my period so I took a test and it said no. So I waited a week and took another and then it said yes.
Depends how late you are,you may have ovulated later.or not ovulated at all,which in turn will make your period late.if you know for sure you ovulated,then you should have a period within 2 weeks.
I tested negative with countless urine & a blood test accept one up until 8 weeks x