Help?

So, idk if its the right place to post this but i am a 15 year brazilian guy,and im being throught some stuff that i need someone´s opinion on,so here we go:

Im having some social anxiety (?) problems,mostly in school,i react in ways i won´t when with fewer pepole,i can´t speak propely and express myself and i can´t mantain focus on things and thats affecting my grades in a very bad way.

Most of the time too i feel like i am annoying everyone by existing,that by someway everyone around me is being affected negatively by my presence,that when someone luaghs and whispers,they are laughing on me.

I know im paranoid but the feeling won´t stop,i also happen to be very bad at making friends and the few i have i don´t talk too much because they have better things to do and better people to talk to (or thats my paranoia getting in)

I feel like i am invisible to everyone:friends,strangers,teachers even fmaily sometimes, i know its common for my age but it still troubles me,that has lead me to feel lonely even where there´s people around.

I ain´t a athletic guy,not fat either but no the one that baths in sunlight playing sports with his best buddies,i rather listen to music or read books or play games with my friends (when they have no one else to play with i think)

I feel like im always the last option,wanna hangout but there´s no one else? call me Wanna play something but all your frineds happen to abandoned you? me Everybody´s got a friend for a doubles test or smth but they have forgotten you? me Your boyfriend happens to be a psycho and no would listen? me,i feel like i care too much for my friends but they don´t give a shit

I feel much lonier then any time before,it feels like i can smile and pretend but inside i just wanna sleep and wake up in a better day,a better world (because everyone is suffering from smth and it happens that our world is like hell to evreyone,even the powerful people)it feels like i can´t do nothing about nothing,that i can´t do shit that nothing that i do will ever change anything and that my life is worthless,my mind blinks in and out of reality and i can´t do shit,i think i should get help from religion,but im atheist (even tho my family is religious) and i can´t seem to find any lord´s light or utter happines forever with faith.

I feel like im dying and losing to the tide but i try to look strong for my friends and family,i can hear my father voice in my head telling me to not be weak,to not cry and asking me if i am a man or not

Ive been listen to music like Linkin park and they have really inspired me,but it feels like nohting really matters,recently im having suicidal thoughts,but at the same time i can´t kill myself because of how my mother would feel,i won´t kill a fly,i don´t need someone else suffering for my pathetic shit.

If you can give me advice other then kill yourself, i would be thankful.

sorry for my bad english and posting coherence