Stressed, sick of parents, my mood is just bla. please help.?

so today i got a test back and i did really bad. it got me really down because i thought i did well, but apparently not. to make things worse, when my dad picked me up he was in a bad mood and took it out on me, he spazzed at everything. when my bag accidently hit his mobile he through a fit. he got pissed off when a girl crossed the road at the wrong time. he called me stupid - maybe as a joke but i don't care, he doesn't realise that it bloody pisses the hell out of me. when we got home he got in a better mood and tried joking around with me but i'm just so angry today that i just ignore him but in my mind im swearing at him and telling him to go die. i have exams this week and i need to focus and study but i can't when my mind is just so BLA. i'm having one of those days where i feel low and can't be bothered doing anything, but i NEED to study. i just feel like staying distant from my family because of the negativity they bring in my life at times. i feel like making myself throw up (haven't done it before but always think about it), i feel like starving myself (haven't done it before, but i also think about it), and i feel like cutting - which i do do. i'm trying to stop myself but i'm afraid if one more thing annoys me i'm going to do it. i can just stay in my room and distance myself from them for the day but that's not going to get rid of the lowness i feel. and how i feel like i'm going to fail at some subjects because clearly i'm not doing well. it's all just overwhelming, i'm in my last year of high school and i'm so stressed because of exams and not knowing what to study in university. i just feel ****, help me.