Help..

Ok..so my boyfriend and I had sex two days ago. According to Glow I was almost done with my fertile window. Today, I was spotting and it was light..so I'm guessing I got my period early? (I wasn't due until Feb.9) Could it be my period or could it possibly be implantation bleeding? I'm confused. Plus, I'm sure it is too early to take a pregnancy test. 😕 Anyone have any idea on what could have possibly happened?