Since last night (after sexual intercourse), I have been bleeding abnormally from the vagina. The blood is light. My period ended this Wednesday. Is this concerning?

It is not uncommon to experience some bleeding after sex, especially if using a water-based lubricant. If the bleeding continues or becomes heavy, it is important to consult a healthcare provider to determine the cause and ensure proper treatment. It is unlikely that the bleeding is related to a contraceptive device such as an IUD. Keep an eye on any future bleeding during sex and seek medical advice if necessary.