Why do I always feel left out?

For some reason I always feel like I've was never liked at high school, because its always hard for me to fit in. almost everybody knows me at school! popular kids, nerds, geeks, ect. knows who i am but they never invite me to any parties, ect. I don't even know why i feel the way that i do because i have people to hangout with, i think that im pretty good looking, i have a taurus personality!! no lie! lol i just love myself and love hanging with people its just that every time i go on facebook and see my friends status its like that they got it going on with boyfriends and parties and lots of friends, and im just there....i know people like me so why won't they ever ask me out or invite me to parties? why do i always feel like this anyways...its SO weird! i love my life but i always feel like something it still missing :/