period two days late and painful cramping! pregnant?

Hi. I am 24 years old and my period is 2days late. I am on a 31 day cycle. I have been having painful cramping, bloating, headaches, fatigue, and sore breast. I have taken two dollar tree pregnancy test and they both have turned out to be a BFN! With my oldest son I dId not get a postive until I was 6 weeks along. And for my daughter which is 2 I got a positive 6 days before AF was due. Anyone else experiencing these same symptoms? ?? Help!