Depends. You may have cracked your sternum, or you may have bruised your heart (inevitable if you did indeed crack your sternum), neither of which can be acertained without diagnostic testing - or on autopsy (bruising of the heart can cause myocardial irritability, which can lead to potentially lethal arrhythmias.) Additionally, your clotting profile is probably a freak show right about now, so internal bleeding isn't out of the question.
tl;dr Call somebody in real life; anonymous message boards are a bad place to get medical advice, especially in an emergency.