Can you still get pregnant when you take a plan b pill after you already ovulated?

Unlikely: If i understand your question correctly .... You ovulated, you took Plan B and you want to know how effective Plan B is at preventing pregnancy. The answer is, Plan B only helps a little in preventing pregnancy after ovulation. The majority of plan b's action is to prevent ovulation. The Progesterone can have some inhibitory effects on fertilization, but they are minimal.