BBT drop but no AF

AF is due today, always starts in the early morning by the time I wake up. she hasn't shown yet today, and it doesn't feel like she will either. my mood of always bad the day she shows, always. I weaned my son at the end of February and was dropped up totally as far as I could tell since early March, but for the last 4 days I have been leaking milk enough to need nursing pads. I know my temp dropped this morning, so she's most likey showing, but has anyone had a drop this late and ended up with they're bfp?