I need some help.

Karli • 24. Louisiana. Pisces.

My period was expected the second of this month. I had sex on my fertile days w/no protection. On Halloween night I had some brown discharge that seemed to be just spotting, I assumed I was just about to start. Well, yesterday and today I had some brown discharge again and it had stopped. I'm a week late and my tests keep telling me negative. Any thoughts?