It is not a separate sentient creature, it is an extension of the woman and her body.
Take a look at this handy graphic you were probably shown back in middle school. Which category does "fetus" fall under?
The stone cold reality is that it's a living human organism, not a kidney. Period. These are simple definitions. Abortion is causing a member of the human species to not be alive anymore.
I'm not here to argue with you and the rest of Reddit about the ethics of abortion, but I always see this "part of my body" argument and it's really just not accurate. It's a separate body which happens to depend on yours for resources, that's true at 1 month or 6 months.
You are a human organism, and the fetus is a human organism. Two human organisms. Two connected bodies. Not one body.