Anyone ever get a late positive?

Belle • Is this real life?
And I mean after missed period late? 
How late was it?  When did you start testing before you got your bfp?? What tests did you use? 
I ask because AF is over a week late and I'm still getting bfns.  It's day cycle day 36 of a typically 27-28 day cycle.
I feel like I'm stuck in limbo.  No AF,  No positive test.