I was wondering up to how much blood can spotting be. Exactly 4 weeks after unprotected sex, I had bleeding, it was like a period but so so light and was gone within 2 days. Normally mine are quite heavy, and last almost a week. And I've just had a baby 12 weeks ago. But now 2 weeks after this small period, I'm getting abdominal cramps. My periods never do this normally.