So frustrated!

Courtney
I have never ever missed a period, or even been late before. I have been on a 28 day cycle, like clockwork, since I was 12 years old. I'm 25 now, so that's pretty dang consistent. I'm currently on CD 38! No sign of AF coming, AT ALL! But, I keep on getting BFN's! What gives?! I know that sometimes it takes a while to build up high enough levels of hcg to get a positive hpt, but I just am so anxious waiting for AF, or to FINALLY see a second line on a test! I feel like I'm going crazy! What's the latest you ladies have had to wait for your BFP in one cycle?