I've (15F) been suicidal for about a year now. Usually, I would change from feeling super happy to extremely suicidal randomly, but now it's getting worse every day. I act completely fine to everyone I know in real life, while on the inside theres endless graphic images of me hurting myself. Currently I feel miserable every day and tbh im getting so sick of it and I want to do *something*, whether it's offing myself or getting help i just have to do something about it and i have to SOON.

so, usually, you'd go to your loving, understanding family for help, right? It's a little more complicated for me. Both my parents have emotionally abused me, and only my mother has physically. My mom can go from insulting everything about me to being super nice and buying me things in seconds. My dad can be super aggressive and scary but then is also more understanding and tries to be sympathetic when my mom hits me.

In general, theyre SO unpredictable??? I have no idea how they'd react to this so im rlly scared. No one in my family has had a mental illness before (at least not that i know of) and i'm really good at acting happy and energetic so I'm scared they'll think i'm lying.

One reason i'm scared to come out is because my mom would probably tell everyone. Once my brother was acting a lot quieter and had symptoms of depression and so my mom thought that he had something wrong with him and was calling all of the extended family and her friends on the phone and describing it in FULL detail n i heard it all?

Another reason i'm scared is how they'll treat me differently. I don't want people to look at me as a fragile person who'll try and hang myself as soon as something bad happens. I don't want to be constantly watched over as if they think im going to do something. Also, my parents have used negative words toward different people at me. They've called me retarded, autistic, and demented (for extremely trivial reasons) 

the only person i can trust telling is my older sister, but shes in her really younger twenties and in college and even though she's a great person, i dont think there's much she could help me with

lastly, i really dont want the cops called on me and i dont want to be put in one of the mental health places (which i cant consent to cause ima minor?) everyone describes those badly and says they make them feel worse and i feel like my mom would call the cops on me and call  me a 'danger to myself' even tho i have never even self harmed or anything

tldr; im scared and my family is kinda abusive and unpredictable pls help me