in July we had done a donor insemination and I didn't think anything of it because of course I started my period a couple of days later then usual, but it was for 1 light day and and day 1/2 of light to faint spotting. then I missed 2 periods after. I took a pregnancy test about 3 weeks ago, bit it came back negative. does anyone know why i might not be getting my period for the past 2 cycles when I am regular almost to the day?? especially when the pregnancy test came out neg 3 weeks ago??