Please Help Me

how do you help a invisible person feel visible. im that type of person because any time i have to do a presentation i feel like im going to throw up like i cant do it. i never in my life done a presentation because i was so scared. i cant get over it i hate that what's wrong with me now im failing in class can someone help me please tell me what i can do to fix those. sometimes when i get up there and everyone's looking at me. i get a lump in my throat and my teacher tell's me to go sit down. then i start crying because i didnt do it and i hate that it's embarssing. there's no one i know that can help with this problem i dont have any friends i dont talk to anybody and when do try to talk to someone it's like im invisible no one hears me. im just another person that no one talks to. everyone around talks to somebody. even the new kids have people to tlak to. im in a military family so its hard for me espically when we move. then it starts all over again im the new kid im just as invisble as i was before. how can i be helped.