My Life Is Crashing Down On Me. LONG STORY WARNING. but please help?

*sigh* okay well firstly let me apologize for any bad language I use during this, it’s a long story so bare with me, if u wanna help me, then it’d be REALLY nice…actually. BTW I AM NOT LOOKING 4 SYMPATHY, if u’r too immature to not take this seriously then please, DON’T ANSWER. Okay, to evry1 else who’s mature enough, let’s say this, my year has been absolutely sh!t. I’ve got my friends in the one corner & my family in the other. Let’s start with my friends, okay well lately I’ve been changing, (not physically) more mentally. I’ve changed as person, I’m not what I was before, I’m different, & the bad kinda different too :( Ever since the begging of this year I’ve been…oh yeah btw (I’m size 6-8 in clothes) yeah well I’ve been, ummm… *bites lip* not…eating. & obviously my friends have noticed at lunch I eat absolutely nothing. my BFF who practically knows me better than myself, always asks me, “are you sure u’r okay, I’m really worried about u, you’ve been acting strange for ages and I wanna know what’s up?” & then I go off and be the terrible person that I am and say something so harsh like this, “OMG!!! damn it can’t you leave me alone for 5 ******** minutes, bloody hell, I’m fine now go away!!!” I said it to her so meanly that she ran off crying and didn’t wanna talk to me all day (can’t blame her). I HATE MYSELF for hurting her like that, she’s my sister (well she’s like my sister, we’ve known each other FOREVER, she’s helped me with stuff in my life, and I’ve helped her, we’ve always had each other’s back, now that I look around and notice that she’s not here, I feel like a monster). I’ll admit again, I don’t eat, but I know why I do it, strangely as it sounds, it make me feel better. Although sometimes, when I don’t eat, the pain it get from it gets soooo bad I have to lie, put on a smile and go to sick bay telling the people there, that, “oh, I didn’t get much sleep last night,” & I always have to change the excuse. I’m so grateful that I have people like this who care about me. I just sometimes forget to show it. My parents (told you it’s a long story, you can leave at this point, it only gets worse), are VERY VERY worried about me, (And yeah yeah yeah, I already know they say it, ONLY cuz they care, they’ve mentioned it to me a 1,000 times!!!) My mother (who I don’t have a great relationship with) said to me once, “I don’t know who you’ve become anymore, I don’t know where my daughters gone, I wish I had her back, but I’m only afraid that she was never actually here?” all that night I cried and stayed up. I won’t lie, I HAVE changed, and I don’t like who I am. In fact I hate who I am, I just can’t remember who the old me was? Where I used to NEVER swear, NEVER shout, I was soooo good, and now all I do is regret. I’m 15, and high school’s pretty much brought everything crashing down (it’s all girls, its catholic, its privet…its hell) beside’s my friends that is. But I DON’T want to go to public, sorry. A LOT of crazy sh!t has happened to me, not only in this year but all my life, I’ve always been a humble person, and I try to remain selfless, but I just don’t know anymore, I hardly ever stop and wonder, “hey, Vanessa, did u know that your entire family and friends have had to go through the same things as u have, GROW UP AND MOVE ON!!?” and it’s reflective moments like this that I realize what I’ve done. please don’t tell me to grow up btw, I already know the mistakes that I’ve made, I don’t need people reminding me :( I’ve lost all my spirit, in the things I do, I used to make everyone around me smile, and I was always soooo positive, I’ve had constant suicidal thoughts now, about killing myself and how good it would be to just go. I know, it sounds morbid but it’s the truth. I need positive advice, & to make things worse, today is my one year anniversary of my nonno’s (grandfather) death. He meant soooo much to me, he took care of me and my older brother for 5 years along with my nonna (grandmother) he died last year (*sigh*he taught me how to me grateful, positive & happy. Now I feel as though I’ve betrayed him. & I’m nasty to my older brother too, we used to be close and he’s very protective of me. but know we just don’t talk anymore, I’m losing everyone…and I’m losing myself. HELP ME :(