Period arroved but BBT didnt drop 🤔

Pam

Hey ladies, i'm TTC and this month my period was late by two days, had some brownish spotting then just one day of real period with red blood. But my body basal temp hasnt drop, it has stayed high since ovulation...is that something that usually happen while not pregnant? First time it happens to me, it usually goes down once my period arrives, or one or two days later.