No AF and No BFP! Help!!!

Jessica
I need some advise please!  I was supposed to see AF on 1/7/16 but she still hasn't came. I tested on 1/8/16 and it was a BFN. When should I test again or could it be something else? My period has never been this late before but I'm so scared that I've gotten my hopes up just to see another negative test. So frustrated!