I can't stop crying.?

Why am I such a loser?I'm 13 and "that shy girl every takes f*** advantage of." Even teachers. My best friend in the whole world has these two other friends who during recess always talks to and they ALWAYS IGNORE ME.I try and talk but it's like they never hear me. I kept trying to tell my friend something but she ignored me and the three of them walked behind me. They looked like they were meant to best friends. I feel like they basically stole her from me. Because Im shy. I have five really good friends but she was like my sister. this happens alot and she's never mad at me and i doubt she realizes how much it;s really hurting me to the point where I have tears leaking out of my eyes in cl while i wear that stupid grin that covers how sad i am. i also have these two girls in my gym cl who purposely mess with me like pushing me. they say it's just for a joke and they love me but i doubt it. right now i feel like im always in the way and all i can do is cry my eyes out. i want to change and actually be proud of the girl i see in the mirror. im not trying to dramatic im really crying here.