Oh wise ladies- I should have asked/told my FS this- but forgot

What day do you count as CD1? Full flow?
It's not uncommon lately for me to spot for 4 or 5 days before my period is due.
TMI- but it's old, brown blood.
I count CD1 as the first day I wear a pad- am I right?

What are the treatments to lengthen your LP?

Thanks