22DPO, 16 days of high bbt and still bfn

[rosebud100117]

we weren't ttc but I ovulated late at CD23 (normally around cd18-19 with about a 33-35 day cycle, 14 day HL). I am now on CD45 and have had high temperatures for the past 16 days. I had a blood test on CD40 and that was negative as well as the HPT I have done, including this morning. any thoughts?