I personally believe personhood and pregnancy begin at implantation of the fertilized egg. I also support choice if the mother was raped or medical needs of the mother, or if the baby will die anyway. When two human lives are involved, I believe in choice as a very last resort for the mother. What if the mother is 10 years old? What if I had been able to conceive a baby when I was raped? Saying a rape victim has no choice, in my view, makes me feel like community property. I do agree people should be married first and use contraception, but hard cases exist. I say this with love, and even if you disagree, can we be friends?
First off, you're right that terrible situations occur in which there seems to be no good outcome. The entrance of sin in this world has really messed things up. As Christians, we have something the rest of the world doesn't - a true understanding of the world as made through God, and an understanding of morality prescribed to us through Scripture that we are able to capture as the foundation for our beliefs.
Thus, as Christians, we should at all times be striving to filter tough moral decisions through the principles of Scripture, not resting upon what we feel should be true, or what we think might be true, but really letting Scripture guide us to what is true. At the end of the day, there are lots of times where I wonder why God did this, or why God allowed that, but I have no choice but to realize that I am finite, God is infinite, I am limited in my understanding, God is eternal. And if I'm going to claim Christ as my Lord, then I need to be willing to let Scripture be my final authority.
All that being said, for me, applying Scripture to abortion is actually not all that difficult from a standpoint of principles, from a standpoint of what is morally right and wrong. However, from a practical standpoint, of actually implementing what Scripture reveals, like with many issues, can be terribly difficult.
I have a few questions for you if you don't mind.
I personally believe personhood and pregnancy begin at implantation of the fertilized egg
Can I ask why you believe this? If an egg is fertilized but never implants, you don't think the woman was actually pregnant? Why? Aside from the location of the fertilized egg, has something about the fertilized egg itself changed from the time of fertilization to implantation?
I wonder why you draw the line at implantation? The implication of such a belief would be that it would make it morally permissible for a doctor to remove eggs from a womb, fertilize them, and then conduct all sorts of experiments in a lab. Those eggs are never implanted, so there should be no moral problem with that idea under your framework. Yet, does that sound morally acceptable to you?
