Advice on how to meet people?

hi im 18 and meeting good friends is tough for me... alll i do everyday is go to school and go home or go to work i talk to people at school , yeah and try to make friends but othing is woeking. im not trying to be something im not ... its just really hard. i dont have any friends really to hang out eith ... everyone just sees me and wallks away ... when i comment on things on facebook related to my prom or anything my comments get deleted or people ***** at me and idont kow why : ( i dont have a boyfiend and dont hae a date to prom. i already spent 600 dollars on my dress and am debating weather i wanna wear it or not just becasue i dont no if i wanna go ... i actually dont have friends im not saying that. im venting on here because i have noone else to talk to.. people say join a club blah blah ... yeha ,, i did that 2 years ago and am still in in but havent made any friends.... not having a date to prom is really hurting me ... it makes me question myself like am i ugly? or fat .. why wont a guy ask me to prom? i already asked this guy not knowing he had a girlfriend and now he doesnt talk to me ... and it sucks because he would always flirt with me and it would make me feel good that someone actually was tallking to me .. you know what i mean? people say to keep my head up and be happy but its hard .... i have been trying to be happy since elementary school .. there i would sit outside by myself and not talk to anyone and would just think once i get to highschool things wil be different .. but no there the exact same... and now thats what im thinking for univeersity ... that when i move away i can just be myself and meet new people that wont have a reason not to like me here. i often cry myself to sleep becasue i cant deal with my insecurities. mainly them being that guys dont like me and people dont want to be my friend ......... i dnt no what to do.......... i cant go to prom by myself ......... i realized that i over think things and cant fix it ... i went out the othe night to the bar and saw this guy from work and he came up to me and said i know you yout gorgeous and it made me SO happy .. you have no idea .. and then we met up again later that night and he randomly kissed me on the cheek and i was like awe!!!!!!!! and then he left the bar holding hands with his girlfriend and yeah i wsnt to upset because i knew they w2ere dating but now at work he didtnt even say hi or anythin aoubt that night, yeah i reallize he was probab ly drunk but really ... i tried focusing my thoguhts on hapy things or other people but nothing works ... help? : ) please