BBT help??

Hi girls, this is the first time tracking my bbt and my third month of taking Letrozole. I had a scan on CD 12 and I had a 16mm dominant follicle.

I had peak ovulation on my opk's on CD 13 at 7:30pm and it was still very positive on

CD 14 at 9am so I'm guessing ovulation would have been on CD 15.

Can someone please explain my chart to me?

Does it look normal?

Thank you in advance ❤️