Help with erratic BBT

Theodora • TTC # 1 IVF 🙏 Unexplained infertility/endometriosis

My BBT has been suddenly lowering, I do it sometimes very early in the morning and it’s now lowered to 36.01 the lowest it’s ever been but last night/ afternoon I was feeling fine at 36.93. Should I be checking so early or should I check later? Because how will I know when I’ll have my temperature dip after my period? Thank you