1.) The old covenant law is all about the letter of the law, the new covenant is about the spirit of the law. If someone "accidentally" killed another (manslaughter), the penalty was still paying with your life. Intentions don't play any part of it. If the unborn child was regarded as a living, breathing human-being, then the woman having a miscarriage alone ought to condemn the person who struck her to death, whether by accident or on purpose.
2.) If the old covenant law distinguishes the unborn from the born, it doesn't change one bit just because we are in the new covenant. The law is different, but if an unborn child is not regarded in the same reverence as the mother carrying it then, it wouldn't magically change just because we are in a new covenant. An unborn child's life in comparison to the mother is not a law that Christ fulfilled and is now obsolete today... That's like saying "apples are not apples anymore since the new covenant... sure they were called apples before Christ came, but that doesn't matter anymore since the arrival of Jesus!"
3.) I agree with you about what God tells me. Personally, I'm convicted that I shouldn't ever do it, but I'd be lying if I said I'm not in favor of things being legal that I am also personally against. Here is a list of things that I'm personally against but I wouldn't want a law passed criminalizing it: pre-marital sex, adultery, alcohol, recreational drugs, country music (sort of kidding on the last one). It's easy to say I wouldn't ever consider having an abortion when I'm unmarried and I don't have a wife with an ectopic pregnancy though. I would of course pray about it with my future wife before making a decision.