Question question!!! Period

So my boyfriend and I had sex last month with a condom, checked it and everything it was fine. He didn't even finish inside of me. I've had pink/ a lot of brown blood but it's lighter than normal. My period gets very heavy. I still have to wear a pad but it doesn't get completely packed like it use to. I've taken three tests and all say negative. I've been super stressed too, could this be my period???? Or should I be worried? Thanks!!!! I'm not spotting it's like a little bit of blood but not my full amount of my period