I dont have any friends, what should i do?!?

lately i feel like i have no friends, there are the people i hang out with but no im really close to. they only seem to invite me to the feild at school so there not lonley or somethig! there is about 9 of us they hag out in two's ( the same two each time) like best friends ian i dont have a best friend! i got close to one girl in the group and she invited nme on hols with her but she is a social climber so im not cool enough for her and we dont even ag our any more so it wouldnt suprise me if she uninvited me on her holiday! Then the 'new' girl i was close to and just the other week she pulled me aside and asked me to go to her sister party with her and i said yeah sure , she said i will sort out the details at school! then today on face book she had wrote on this other girls wal... did you get my text , van you come to my sisters party! i was really upset. and its not like i dont try to be friends with them, i have then over for tea and sleepovers! i have cried so much over this all i want is a firnd to be close to i just want to be able to confront them and say why did you do that? why did you ignore me ... and so on! Also they never wait for me after class even if our class rooms are next door!!!.