insecurities (sorry for the long post)

i live in an environment where people all around me are narrow minded and judgemental. ive gotten so many remarks about my body, how my thighs always touch and rub against each other , how big my thighs look when i wear shorts , how big my arms look when i wear my basketball jersey. i remember, the past few years of me getting bullied my all my friends around me for being fat. my coach , made fun of me in front of 5 other different schools and my own school team members during a basketball match two weeks ago, saying i eat so much and am so fat yet couldnt be able to throw a basketball harder and more firmly. i was shattered. ive never been insulted by an adult for my size , moreover my coach of my favourite sport. the only sport ive not given up on ever since i joined. i love basketball, it's like my second home. but my coach judges and makes fun of how i look so often, and i can't find the motivation to be physically fit. i do sports everyday , yet i can't be able to increase my stamina or get to anyone's physical level. i constantly look at my body in the mirror and just see a naked body filled with disappointment. i'm not exactly tall, i'm 155 and 51kg. and everyone i mix with , has a body of a model , although i'm not even past highschool , all the girls i mix with excels in sports and some in academics , and theyre either tall , beautiful or curvy in a slim and fit way. makes me feel really self conscious. i don't know what to do with myself , i see a droopy stomach hanging out everyday, and my big thighs rubbing against each other whenever i walk , and my arms practically looking bigger than a guy's pair of arms ever and they aren't muscles. i feel really demotivated , lost , also , my love life is a mess. i'm in need of help, but every time i talk to someone i know about my problems they try to motivate my otherwise by saying things that clearly aren't true , i'm fat, i see my belly drop , my thighs touch , my arms don't fit tight fitting clothes like the way i want them to. i feel like a nuisance talking to just anyone about my insecurities. please help.