How do I make my friends interested in me instead of being the back up, fifth wheeler?

In eigth grade, I was separated from all my real friends and they all went to different schools and just distanced themselves and I no longer talk to them. In ninth grade, with only 800 people in my school (first year) I don't have ANY real friends. I mean, they're my friends, I apprieciate them, sometimes I laugh with them, but I feel like I'm just the back up friend that they hang out with when no one is around. Whenever I try talking to them they just give me one word responses and go with my other "friends". And, whenever we're all eating in the cafeteria and someone is still eating, such as me and my sister, they just say "lets go" and they just stand up and leave me alone...And they never even wait for me when we're walking in the hallways, just leave me behind and sometimes it seems that they're trying to run away from me. Also, they're really different around me and my friends and in class with other friends. When they're with me they're really quiet and when they're with other friends in class they're all really loud and they always **** talk about people for no reason which I absolutely HATE. They're never here for me when I need them, and I feel like they just talk to me when I'm bored. It has nothing to do with my looks or anything. Somethings wrong with the way I talk, I can feel it, but I'm not sure how to improve it. How do I be more interesting and make new ACTUAL friends?