I use OPKs, CBEFM, and chart (I know, a bit overkill). I got positive OPKs starting the evening of day 14 through the evening of day 15 so it looks like my LH surge was mostly on day 15. OPK directions say I should O 12-48 hrs after LH surge so I should have O'd on day 16 or 17. FF is giving me crosshairs at day 15 which doesn't really make much sense to me.
I typically O on day 17 or 18 so this day 15 one seems odd.

Also my temp doesn't continuously go up after day 15 like it should if I actually did.

Based on my chart, when do you think I O'd?