Hmmm...have you and your husband had unprotected sex recently? If so, then there is always a chance of pregnancy. The small bit of blood could be implantation bleeding. But it would be too soon to tell for sure if you are pregnant or not. The best thing you can do is wait and see if your period comes next week, and is normal. If it does and the bleeding keeps occurring even after that, then I would see about visiting a Doctor. If your period does not come next week, then take a pregnancy test.
Good Luck