I did not address that issue because there is likely nothing I could say that would change your mind. Most people’s beliefs about when personhood begins are based on religion, and there’s just no arguing with that.
However, there are quite a few excellent arguments about the morality of abortion that assume for the sake of argument that life begins at conception, and make a convincing case that abortion is still not immoral. The most famous of those arguments is Judith Jarvis Thomson’s paper A Defense of Abortion:
I encourage you to read that and see if it answers your concerns about abortion if you really believe that a fetus the size of a mouse, which cannot live outside the uterus, is a person with as many rights as an adult woman.