Hate people speaking behind my back :(?

You know what? They are probably jealous that you have a high metabolism, and therefore feel the need to attack your weight because they are insecure about theirs. They don't seem like very good friends anyways, maybe you should find new ones? I know how hard it is to be made fun of, especially for something you are self conscious about and are trying your best to change. Make it clear to them that you don't want to be around people who talk about you behind your back.