I Took The Levonelle Tablet Last Wednesday Morning, 12 Hours

I took the levonelle tablet last Wednesday morning, 12 hours after intercourse. There was no ejaculation as I stopped it early on. Then the next morning to be safe I took the tablet. And Monday evening (6 days after taking it) I noticed a small bleed and since then I have been bleeding a little bit, almost like a light period. How long does this last? I did notice that it is a common side effect.