Hi. Please enlighten me. Is there such a thing as a false negative in beta hcg blood tests? LMP was Aug. 16. I have a 35 day cycle on average, longest was 40 days. AF was due Sept. 20 but still not here. I'm on Cycle Day 43 now. Had sex with fiance on predicted fertile days, been TTC since January. Home preg tests all BFN as of Friday Sept. 26 as well as beta hcg blood test. I have a long ovulation window and I have PCOS but been having AF consistently every month for more than a year now. I couldn't know for sure if I ovulated though because I was planning to start checking CM and BBT this cycle but AF still not here. My CM for the past 3 to 5 days have been odorless, clearish white, not too plenty but enough to have a somewhat thick or moist feeling as if AF were here but no AF. Never experienced cramps before even with PMS and AF but lately been feeling mild cramps but not to the point of being painful, just a bit uncomfy. What could be going on?