CD 10 not but drop after ovulation but af has been and gone.

Hi everyone, I'm on my fourth month of tracking bbt and just wondered if anyone had any thoughts. My bbt cover line has generally been 36.75 with a drop around 3/4 days into af and one month 1 day after it finished. However I'm CD 10 now and my temp has consistently been 36.8. Normally I'm around 36.2/36.3/36.4 at this point but I don't seemed to have returned to normal bbt yet. Had anyone else has this or does anyone have any ideas????