Ovulation & Trying for another

so recently my fiancé and i have been trying for baby # 2 and about 5 days before my fertile window opened we were trying and i am now 2 days from it ending and we had sex everyday from then till now; so today as i'm going to the bathroom i notice light bleeding and now it's gotten heavier and this has NEVER happened to me before. could be implantation bleeding or something else?!