could I still be pregnant?

Ok so what are the chances of actually being pregnancy and not my body just screwing with me? I'm 3 or 4 days late and i tested negative this morning. What is the latest some of you ladies have gotten your bfp? If I was pregnant should it show on a test by now, the last time I was pregnant I didn't get a positive till about 5 1/2 weeks and miscarried at 6 weeks. So that worries me also