8 days late & BFN

TTC: I was on BC for a year and a half (microgestin). I got off BC 07/26, I did get AF on 8/2 which lasted about 4 days which is normal for me. On my calendar it says I was supposed to get AF on 9/3. So I'm 8days late and I've tested several times and all I've gotten are BFN :( . Has anyone who's been on BC and gotten off it had this problem? How long after getting off BC did u start having normal cycles?