mother withholding SSN & Birth Certificate

So I turned 18 in January and my mom and I made an agreement that I have until I'm 19 to move out. However since then every fight we get into she always ends up threatening to kick me out and is always saying "I fucking hate you, when are you gonna get a job and move out?" Just this last Monday she was yelling at me to get a job and even said "just be a prostitue because you have no fucking skills anyways." As well as a bunch of other "I'm going to kick you out if you don't blah blah blah" the thing is she says this when we argue but then any other time I'm apparently "not allowed" to get a job. Well I want to move out with some people by June, so I need a job (I've had them before but always during summer). She won't give me my social security to apply for jobs, and she won't give me my birth certificate either. I have no idea what to do, I don't want to live with physically abusive, emotionally/verbally abusive mother anymore and I can't handle having my home constantly threatened every time she's in a bad mood and feels like taking it out on me. She has all my legal documents locked in a fireproof box she has hidden, as well as the key is hidden. 
As far as I know I need my birth certificate to get a duplicate SSN Card right? 
Edit: I need the card bc I don't have the number memorized, which I realize now is my own fault.