I did it, I POAS this morning and it was negative. I'm not suprised at all. Even though I have no symptoms of pregnancy or of AF arriving anytime soon, I wasn't suprised to see the single line. Hard to believe that in 37 years that I have never seen double lines.
Going for Beta on Thursday but it will just confirm what I already know.
Maybe one day I'll see double lines just not this cycle.