I’m not trying to be critical, but I’m not sure that’s a logically consistent prolife position. It is similar to saying that you would shoot at the wall of a building, not knowing for certain whether anyone was on the other side. That would constitute a reckless disregard for human life. Any time lethal force is used, there must be certainty that the target is a legitimate target. If conception has occurred, there is a living human being present, with rights of their own to consider.
I recognize you most certainly do have a right to try and get back to square one, but not at the expense of an innocent human life. I can tell you from personal experience with people that I love, any person might feel justified at the time of the event, but a person of conscience will keep coming back to such a decision like a wound that will not heal, and will always wonder what it might have been like, if they had withheld the fatal blow.
I would take the pill, eliminating that raper from my life, and think no more about it. It is highly unlikely that one time would cause a pregnancy but I wouldn’t take that chance.
Taking a birth control pill prevents many babies from being born, just like the morning after pill if one took that pill every time. A man wearing a condum prevents many babies from being born. That’s just the way it is.