AF is late.

So, AF was supposed to start Oct 1st but has yet to show. I know I'm only 3 days late, today would be number 4 if she doesn't show. I've taken multiple tests and all have been negative. I've never been late before. I've been feeling cramps, like period cramps but not nearly as painful which makes me think I've finally started, only to go to the bathroom and find it that I haven't. I guess I'm wondering if there's any way I could still be pregnant, even though all I'm getting are negatives? Thanks in advance.