Lost and confused help ):?

every time I get close to people I feel like I love them, and I push them away, because I feel so dependent on them and I don't want to get hurt, but when there gone I feel so alone and depressed because I need them because they are everything to me. This is badly worded but I'm so depressed right now, I feel like I'm going to be alone forever, I drink and get high a lot and people think I'm fine, Im trying to get over the self harm I inflict, but every night I think of it. I feel suicidal, trapped, alone I don't know who I am, I cant accept myself for whatever I might be, and I don't know what to do with myself, my mum has no idea about my life so I can't see anyone about this, what should I do ):