Did I test too early??

MissK
I have had pregnancy symptoms... But I cant tell if they are AF or not?
​My cycle is usually about 27 days, according to Glow I ovulate on CD18, I should get AF tomorrow, and took a test (not a FMU, and just a cheapie) and it was negative.  
​I am currently 8 DPO-- is it possible I tested too early even tho AF is due tomorrow?