I just read on another thread that apparently if you have a high metabolism, like I do, it can take hcg longer to be detectable in your system, which could explain why I didn't get a bfp until I was 2 weeks late with my last pregnancy, and why I'm not getting one now. This is the first I've heard of this, so not too sure how accurate it is, just a little food for thought. I'm going to read in to this a bit more.