Implantation or period starting?

Charlotte

13 DPO and period is due in 2 days. 2 days ago (4 days before AF due) I had a little spotting when I wiped after me and SO BD.

Since then (last day or so) I only get a little bit when I wipe, nothing on the pad. BFN when tested 3 days ago.

Periods are never early and normally come at full force from the start. Been TTC for 10 months.

Any advice is appreciated.