Confused

It's been a while since i post something but this is driving me nuts. I honestly don't remember if I had my period in June or not. I'm sure i didn't have it in July then I realized i haven't had my period in early August so I took a pregnancy test around 5-6 am and it was negative. I've been waiting since for my period and still haven't gotten it. I have sore breast and cramping. I understand those symptoms can be for ovulating but it's been happening for weeks. I've been told i'm probably just overly stressed but I still don't understand how it can make my period be late for 2 months. Need advice