Salam sayang! Ini memang boleh jadi banyak kemungkinan, bisa implantation bleeding, bisa dari perubahan hormonal, atau ada micro-tears dari aktiviti. Tapi sebab darah campur keputihan and the timing tu agak unusual, please go see your doctor or go to clinic as soon as you can , okay? Bukan panic, tapi better safe than sorry especially since period history mo agak off. A few of my mum friends pun pernah experience similar and turned out fine after check-up, tapi kena confirm dengan doctor lah. Don't wait, just go eh!