cutting off my toxic sister?

this is kinda a rant. I need advice. so I’m 19w5d pregnant... I have a twin sister who I grew up with. we were best friends.

Lately, since I got pregnant, she has been so extremely toxic. she was toxic before but being pregnant it’s really taken a toll on me.

When I first found out I was pregnant, my mom told her. I didn’t want her to but she did and I understand why my mom couldn’t keep that from her.

Then, immediately after, my sister got mad at me and angrily told my dad and my older sister,

Since then, I haven’t really been able to talk to my dad about it. He got to hear it from my sister when she was angry and not me.

She also sent me a couple very long mean text messages.

She said I ruined her life, my mother wouldn’t pay for her college classes anymore, I was going to fail as a mother and my child would get taken from me or be neglected.

My mother was still paying for her classes, and had no plans to change that. But my sister stopped going to her classes on her own free will.

Now a few weeks ago, she texted me about something. she told me she had sex with a guy, and his pregnant girlfriend found out about it. she also threatened to beat up the pregnant girl because of it. I don’t know why she would say that. She’s hit me before, and I’m pregnant too.

she also came to me about having sex with another guy who has a girlfriend, and also another guy she wants to hook up with who also has a girlfriend.

This might not seem like my problem, but it has put so much unnecessary stress on me. I am having a boy, and I cant bring myself to let my sister around him. She thinks it’s “fun” to purposely hurt people. She says “I might be a bad person but at least I’m having fun”

I dont want her to teach my child that that is okay.. I want him to love and respect people, and to love and respect women. Other things have happened between her and I but these were the times that really stressed me out. I haven’t said anything yet about... she scares me so much. I’m scared to say how I feel because if I say something she doesnt like, she harasses me and sends me horrible messages. she posts all over her social media about how horrible I am.. she even told her Instagram I was pregnant before I said it to anyone. I’m so scared of her but the past few days I’ve been stressing so much trying to think of what to say to her. I need to cut her out of my life but I don’t know how. My fiancé agrees that he doesn’t want her around our son, but ive told him not to say anything. She told everyone her ex abused her because he decided to move on from her, I don’t know what she would say about my fiancé. I’m sorry this is long.. I just need help. My mom is the only person I’ve thought could help me but she doesn’t want to get in the middle. Please no hate..