Don't know how much longer I can take this

School work has been building up and I feel like I'm dissapoiitng everyone around me. I have to send my dad a letter and I don't know where to even begin, I can't even tell him half of the things I do because I know he woulnd't aapprove it. I failed a class and now it's dropping my GPA even though everything else is passing with flying colors, I'm about to be tens of thousands of dollars in debt because I have to go to college. God forbid I bring up anly other career choice infront of my familt, Then it's all of the sudden they never believed I had any interest in anything. I'm not even eighteen and I'm supposed to have everything figured out, College is too exspensive and someone like me could never get into a career in art. I'm not good enough and don't have the money for camera equipment. I feel like I don't belong anywhere and no one likes me. The person I thought was my closest friend talks behind my bacl and doens't want to talk to me anymore, the only time we talk is when I try to start a conversation with her and then I'm ruinign her day apperently. And no one could be better than her at nything or she starts crying about how we're stressing her out, and we know that she has problems. She makes everthing about herslef. I tyr to make plans with her, but then she ivites her other friends so it's a big group. For homecoming I asked her a month in advacnce if we could go out after to eat, and she said she swore to make up missing all of out other hang outs and go out for dinner. The day before she comes up and says she and her other friends made a reservation and she forgot about me. If I did that to her she would've freaked out and made a big deal. It just feals so lonely. I offered her to smoke weed with me while we were on summer vaction, and she was acting like I was shoveing herion in her amr. I wouldn't have even offered if she hadn't been asking about it the day prior, talking about how she really wanted something to smoke. She called me a druggie who was gonna end up dead in a ditch. My entire familt is nothing but addicts, It's not how ads at school show us. And that weed is the gateway drug to cocain. And I try to understand from her point of view, maybe she was just having a bad day. But now she's acting like i'm this druggie who cornered her and tried to get her to smoke weed, she's talking shit about me to everyone.