That's... that's so bad I'm so sorry.
Okay look, I hope you know that you won't be forced to give an interview. And if you're under the protection of social workers then it's even better. You can never be sure when your father hits his limit and actually commits suicide.
Don't take risks and contact the social worker. Ask for some protection and they'll definitely give it to you! That's their job.

And I have anxiety as well. It's a horrible thing but spending time with your loved ones can help. If you still aren't convinced about leaving, then try to spend as much time as you can outside with your sister. Taking walks with her and stuff like that. Try to study in between that time. If you can, then lock yourself inside a room when you're studying (Preferably with your sister in there too) and don't come out until you're done. When you're not studying, listen to music, watch movies, read books. Anything that's enjoyable and takes your mind off things. Research on jobs so that it gives you somethinig to hope for.

I know this isn't that helpful but you're strong, you'll get through this!