Gilli, my sister got her membranes swept/stripped and she had similar discharge for a day or two. A week later, her doc did the same procedure again. Again, she had cramping and bloody discharge. However, within 48 hours, she went into labor. The procedure works if you're ready to go into labor, otherwise, the mucus plug regenerates/builds back up, I've heard.
I got my membranes swept two days back. I had no bleeding, nothing.... The doc said in the procedure they separate the cervix from the water bag. This supposedly causes prostaglandins to get released, which can stimulate labor.