i started bleeding approx 7 days before my period was due. i was hopeful that it may have been implantation bleeding as all teh timings were spot on, but having done 2 tests which were negative and had my period now, i am concerned as to what it could have been. the bleeding was normal oxygenated blood. not pink not brown and lasted a week, very light before my cycle appeard to start. My period was lighter than usual but not overly so. its the first time i have experienced this and i can't help wondering that maybe its a sign that i won't actually ever get pregnant.
from time to time, a woman's hormonal change can cause her cycles to be different especially depending on her age, I too have experienced this.