How does a pill abortion work?

I read about it, but I want more advice from people who have done it, because I'm afraid that if I do it, I might give birth to a fetus and that scares me. The pharmacist said I need to wait 10 more days to see if I'm pregnant because my period was 30 days ago, and to see a result I need to wait 10 more days. What I want to know is if I do an abortion pill in this incipient stage in which it's not even a fetus, just a bunch of cells, how will it be? How will I eliminate it?
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Update: I found out he was cheating and there was a probability that she would be pregnant too, so I went and did a blood analysis, and it's negative, so the doctor said I'm not pregnant, and also I'll wait a few days to do another pregnancy test. About the guy, I left him and never wanna see him again, I thing the other one also left him, but apparently there was a 3rd girl who is already 3 months pregnant, but I don't know if that's a lie or not, either way, I left him
How does a pill abortion work?
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