I'm lol new HELP

mary
Ok i ovulated the 28 or 29 of July so today is August 10 so am I 12 dpo? AF is due next Sunday August 14 I have taken a few test bfn I have done cheapie the last few days but also did FRER THIS MORNING NOTHING...any advice wood help Iis anyone has gotten a late bfp and about my dpo do i have that right???