Pre-period spotting

Hey,

For quite a few months now my period had this weird habit - before it officially comes, for two days I have some light, brown spotting. We’re not yet trying for a baby (we’re in the, sort of, pre-TTC getting ourselves on track mode), so it’s not implantation bleeding. It does this every month. I just don’t understand why? And (sorry, TMI!) when on one of these spotting days I go to the toilet (#2) I bleed for two seconds, and it’s bright red blood. And then it stops for a day until I officially get my period. Does anyone know why this might be? Thanks in advance :))