So you got pregnant on birth control, which is completely normal. It has ~2% chance of happening, if I'm not mistaken.

I understand that your mother is upset but there is no excuse for her to speak to you like that. Shes an adult, and she needs to attempt regulate her feelings. It isn't constructive at all. I would get an abortion as soon as possible. I don't know what your pockets are like, but what we do know is that after three months, you can no longer get an abortion. If you can no longer get an abortion, I think you should try to have a conversation with an state agency that can help you navigate this. I know in New Jersey there are residential homes for young expecting mothers, and great adoption agencies. Those same state agencies can help set up family therapy for the both of you if recommended.

You will be okay. I speak from experience.