I am hoping for some help/confirmation on how to accurately (as possible) work out how many days past ovulation that I am, as I think I’ve been calculating it incorrectly!

So I got an ALMOST positive OPK test on the morning of 03/09 and then what I believe to be a positive OPK test the following day on the morning of 04/09. (Photos below). The next day the OPK had returned to negative (much fainter).

So am I correct that it is likely that I ovulated the following day on the 05/09 and therefore my first DPO would be the 06/09 and that would make me 8 DPO today (14/09)?

I took a pregnancy test this morning thinking that I was 10 DPO hoping to see a faint line but it was undeniably a BFN, but if I am only 8 DPO, I’m assuming it would be far too early for a positive!

Any advice is appreciated! 😊