Is shy and friends are starting to leave me...?

okay so one of my friends decided to completely ignore me. i had invited her to my birthday party and she told me that she will text me if she can come because her dad had just had surgery. That afternoon i called her and lefts her msgs but she didn't answer any of them. She didn't come to the party and since then she completely ignores me at school. I even sent her msgs on facebook but she deleted the ones on the wall and all the comments i had on her pictures. She was my first best friend and we have known each other for about 10 years and suddenly she wont talk to me? oh and she plays all cool when she is with her "new" friends. I am sure that i didn't do or say anything about her to hurt her or something but she is hurting me right now. I don't know what to do i don't want to talk to her cause she has this tomboy friend nd shes not very nice. my friends think its jealousy but then again those friends decided to through a bunch of s**t at me that im not nice to them or whatever. I never say bad things about my friends or talk to them in a bad way. But they seem to do this to me! I hate that now i only have two best friends. one who i only talk to on msn messenger while she has many friends and doesnt even talk to me at school and the other one doesnt go to my school so we see each other once a week. So at school i mix with my classmates but just today ones of them said in a "way" that im fat and lazy. Actually im skinny and i do breakdancing. So i basically have no one left and that makes me feel really bad. im not very social sometimes and when i talk im nervous so i say odd stuff. I really want to solve the problems that i have with my friends and make more friends and become more social cause when im at school i feel like im in a bubble that doesnt speak to anyone and is shy..! please help me.. what should i do? x