Help!

Laney

Okay so my boyfriend and I had sex a month ago. Well almost 2 weeks ago I had a period but it was 3 days long and it was super light and it was a rusty red/brown color. Well yesterday I was cramping and I went to wipe and it was a very rusty brown color. The discharge or spotting is super light and I took a pregnancy test this morning and it came by negative

. Can someone tell me what this means.