C.F.
I would take another pregnancy test. Could be the first one was too early. Also, if you are TTC, check out Natural Family Planning Ovulation Method, which can help you determine ovulation and thus know exactly how long to wait before taking a pregnancy test. This type of bleeding can occur in pregancy, but it is possible just to have a very light period as well, with not a lot of "fresh" bleeding. If the bleeding stops within a couple days and your body returns to normal, it was probably just a light period, but if it were me, I'd take another test to rule out pregnancy. Good luck.