trouble in life...

Lets start from the begining.
I have to share a room with a 7 year old, and she is annoying. She always tries to take advantage of me, and "act older" than she really is. She was being SUPER annoying last night and she was in my face. so i push her away. but i guess i dont know my own strength cause i knocked the air out of her, and she couldnt breathe for a bit. Of course i started to panic and she started to cry. so i took her out into the living room to our parents. she then told a lie that i hit her and tried to beat her up(i wouldnt do that to her, if i was trying to do that i wouldnt have brought her out to our parents) and of course my dad belived her, then slapped me. On the face. i can still see the hand print, and its been more than 12 hours. I then had a relapse. he said that later he would take my phone and laptop away. ALONG with my flute, guitar, trombone(etc..) and hes gonna pull me out of band class, choir class, and im going to fail my end of year concerts cause im grounded until he gets tired of seeing my face everyday...
I tried to commit suicide.. my throat has a few scars from wear i cut it, but it wasnt deep enough.. so i stopped for a bit and decided i wanted to write a note to my mom first, and tell her i loved her.. i did that and i felt better.. but not happy. i tried with the knife again and i knicked one of the veins in my neck and passed out.. but the cut was small so it closed up a couple mins after.. i woke up at 6am with my arms and neck covered in blood... Luckly i washed it off before my mom could see it.. i dont need one of those 24 hour suicide watch gaurds around me all the time.. or even having people around non stop...