Actually, Michelle, you got me thinking and I have to say I'm a little confused. I wonder if you ladies can help. I'm still pretty sure I'm starting to AF, but I read somewhere that "most women feel implantation symptoms shortly before their period should begin" and that during implantation CM is a slight brownish or pink. Well, I've definitely had cramping for several days now and a few other odd symptoms, and CM right now is a very light brown. I don't remember having so much cramping leading up to AF and also so far in advance, but anyway, my point is that I always thought HPTs can only show BFP once implantation has occurred. IF implantation hasn't happened till now, it would explain the BFNs, BUT if the average luteal phase is 14 days and implantation can take up to 12, how can FRERs so confidently pick up on BFPs at 9 or 10DP? Oh... I guess the 76% positive rate (or whatever) is based on that percentage having implanted by then? So I guess HCG levels rise IMMEDIATELY after implantation? Argh.. sorry... I think I answered my own question, but still worth floating to you guys in case I'm mixing things up. But even if I'm right, I don't know how likely it is that I could have BD'd on Jan 10 and 11 and had the swimmers hang around long enough to catch the much later ovulation that would be needed to implant right now... right?