okay, was just wondering if maybe you had implantation bleeding if it was only 1 day long!
From what you've said about your usual cycle length, I'd say it is unlikely you've Ovd and its because your temps dipped so low down during AF (which is common) that FF is picking up predicted Ov so soon as your temps have just gone back up to usual temp.
However, CD8 does look like an OV dip... would be very early though! Have you had any EWCM?
If you keep temping you might find FF readjusts its Ov prediction.
Thing is with BBT charting, it isn't until 3 days after Ov that you find out you have Ovd so you can very well miss your Ov & FW. But it is good to find out your LP length and have a rough idea of when to expect Ov for the following cycle (if your cycles are regular). I BBT chart so I know when I've entered the TWW and so when to expect AF as my cycles are so irregular.
Keep DTD every 2 - 3 days and you shouldn't miss the FW if you haven't Ovd already.
It is your first cycle charting too, always best to not expect too much out of the first attempt as you've nothing to compare to. Once you have a cycle or 2 charted you'll be able to compare and see patterns a bit easier.