Bleeding 2 weeks before period

I had sex with my boyfriend yesterday, but he did not cum in me. I am on the pill, but never have felt comfortable to let him cum in me. 2 days ago was my “ovulation day” according to my FLO app. However, I’ve experienced some bleeding today and some dark brown discharge.... does anyone know why this could be happening ? I’ve read it could be do to vigorous sex... I also have been super stressed out lately as well.