Anyone else experienced this?

I have pcos and am ttc baby #1. Im 24yrs old. I started my cycle on august 6th ended on august 11th it was a normal cycle for me. Then on august 20th i started bleeding again but only from the time i get up to about 4 hours after ive been up and moving around. Its light bleeding but more than spotting. Any ideas as to what it could be?