Af late, possible pregnant

Natasha
My af is 3 days late, I was suppose to come on 9/4 and I think I'm pregnant but I haven't had any symptoms. Is this normal? My af is normally early or right on time. I had really bad sharp cramps 4 days before I was supposed to get my af is that maybe a symptom? Now 4 days late took a test this morning (first response) it was negative is it maybe wrong?