I'm so lost!

Kr

I'm 40, DH is 41 with no known fertility issues, no miscarriages, no multi-month ttc, no medications, and I was pregnant only 1 time 22 years ago, and haven't tried since. Ok so, DH decided to change his mind back to ttc after we made a lifestyle change and settled down. I had quit tracking, but was luckily able to pick it back up in time to catch important info. We DTD 2 days before O and day of O. BBT partially confirmed O and PdG officially confirmed it a few days later. Follicular phase BBT is usually in the 96°F range and picks up to 97+ after O. With that said, I can't figure out what's happening. I had significant cramps without bleeding the morning of 10 dpo, exactly like the only other time I felt this when I conceived 22 years ago. Super tired until yesterday, but I saw bbt dropping just to see a baseline drop today! Neg hCG, not unusual for me either. This BBT drop has me lost with the 10 dpo symptoms. Otherwise, I'd assume AF is arriving. Does anyone have any ideas other than obviously waiting for AF?