Ib? Orrr

Okay I’m not completely positive that’s what it was but I’m kinda hopeful. Please read and give input.

My period is 4 days late now. 4 days ago I had sex, after we were done my so was like “your discharging” I was like ummm we that could be you. And he was like “no, it was kinda a light brown.” So I was like hmmm my periods probably coming. I took a pregnancy test the following night when I woke up for work, there may or may not have been a vvvvfl (hate those dang things). But I then tested after my 16 hr shift and absolutely nothing. I’m thinking maybe that could have been my ib because I haven’t spotted or started bleeding. I’m going to test in 7 hrs when I’m off work again, but is that possible that I had ib?