depression and anxiety someone help

i've been feeling like this for years but it's been getting worse recently. i have anxiety attacks almost every day and cry myself to sleep almost every night. i can't even imagine telling my parents. it's not just that i'm sad, i don't want to be a burden and i feel like everything i do is annoying to people. i can't make new friends ever because i end up scaring them away somehow. i struggle with body image issues because i'm 15 and almost 200 pounds. people think that i'm happy but that just shows how good of an actress i am because i can't even remember the last time i was happy. people don't think i'm even remotely funny or anything like that. i make a little joke and all i hear are crickets. i'm probably not explaining this very well. i just don't know what to do anymore. every time i think about telling my mom, i think about her taking me to a doctor and it makes me want to hurl. i don't want to feel like some psycho basket case who can't handle her emotions. if one more person tells me it's because of pms or hormones i'm going to freak. i've felt like this for years before i started my period. i have suicidal thoughts pretty much everyday but i'd be too scared to go through with it. because i'm scared of everything. i don't want to be me anymore. i hate every single thing about myself. i can't tell my mom. i can't see the look on her face if i told her. she would be so disappointed. and i can't even imagine her telling my dad about me. god what am i supposed to do. i feel weak in the knees all the time. i basically live with a migraine and all i do is sleep. my sister is super popular and has perfect style and the perfect friends and i just want to be like her. but she won't stop bugging me about not having as many friends as her and she judges everything i do, say, or wear everyday. i'm so so tired. all the time. what am i supposed to do

EDIT: i had been going to the gym and was on a diet for over 2 months and literally nothing changed at all even though i was trying really hard