Hello Good Evening,
According to your description, you might be gone through missed abortion
The theory between your conception that, your egg met to sperm on 8th day of your menstrual cycle, which is less possible but not impossible.
So you got pregnant, but due to some unknown reasons you gone through miscarriage
, which can be happens in around 25% pregnancies without a specific reason.
So be watchful on your bleeding now, and do a visit to gynecologist for a USG for confirmation of abortion and conservative management.
Dr. Naresh Jain