What's triphasic pattern? I'm 9/10 dpo today with mild cramps and lower back pain.

Maria • Happily married. #1 baby due June 2022. ❤️ PCOS. Bicornuate Uterus. Chemical Pregnancy in 2015. 🌈

Today my temp went higher and my app predicted a triphasic pattern. Can anyone help explain? I've been taking pregnancy test yesterday and today and it's BFN. So I'm not sure what to think...