I am on a depo-trust injectables since I have an endometriotic cyst. Depo-trust is also a contraceptive. May boyfriend and I had coitus on the 13th day since my depo shot. Will I get pregnant? When would be the onset of effectivity of a depo shot starts? Should I take an emergency contraceptive pill?

While there is always a chance of pregnancy, even with a contraceptive, your odds are quite small. You can consider the injection effective within several days after you receive it.