BBT question

✨Sarah✨ • I`m 29, married for 6 years (together for 11!) and TTC #2. We have a gorgeous 5 year old girl who is starting kindy soon
So I only started BBT this week, I'm currently 9DPO (estimated, based on CM and ovulation pain) but since I've been taking my temps they have been gradually dropping... I only started temping 4 days ago. But, your temp is supposed to drop leading up to AF, if I were pregnant they'd stay high, right? So I'm probably not pregnant 😔