Can you have a temp drop and still end up being pregnant ?

I am 18 DPO. I tested monday and got a Vvfl after 10 minute mark so I chalked it up as a negative. Heres the chart

But the drop occurred yesterday and today yesterday was 97.9 today 97.65. AF hasnt been this late last few cycles. I just cant make myself test again and see another negative line so im grabbing at straws

Update****** for me unfortunately this meant AF. I was 5 days late.