Late period, BFN x4 - some spotting

[tuxie11]

I'm on CD37 out of a usual 28 day - I say that as I was regular before 10+yrs on the pill, came off in Dec, had withdrawal bleed & went into 28 day cycle.

TTC month one - taken 4 tests as I was late and all negative (FRER & Tesco) which I'm fine with.
Past 3 days I've been spotting - first time ever, with some brown and now a little more red tinged blood which I am hoping turns into AF.

I'm aware it's likely that my cycle is getting sorted as it's only my second, and I can't pinpoint O as I don't chart/OPK (nor do I want to just yet) so it's likely I O'd late OR I didn't O at all (would I get AF in that case?)

My question is if for whatever reason I don't have AF - do I just keep counting the CD until I have something that is most like AF?
At the moment bleeding is probably medium - enough to warrant a pad but not like typical period flow.
Just abit confused on how I should count this

Thanks