AF 2 weeks late, still getting BFN

Karen
Has anyone experienced this? I have endo, but I have never ever had a late period, or skipped one. I started taking BBT again after I was 2 days late. I had stopped because TTC was starting to stress me out and I usually ovulate on CD 15, so we have a good shot of hitting it. My BBT is WAY higher than normal pre-O temps.
 I'm going to wait until my next AF is due before making a doctors appointment because my work schedule is really crazy for the next couple of weeks.
I'm less stressed than I've been in about 2 years, so I know it's not from that. 
Has anyone been this late (or later) before seeing their BFP?? And if not, what ended up happening?