I’m so upset with my figure 😭😭😭😭😭

I am 15 years old, I hit puberty when I was twelve, my sister and mum are both super cute and skinny and I’m so so so disappointed in myself for letting me get this big. I hate trying on clothes cause nothing fits and then my mum gets all annoyed cause I get in a bad mood when we try on clothes. I’m so jealous of everyone I know cause all my friends are skinny aswell and my sister being a sister points out a lot that she is skinny and pretty and I’m fat and not pretty. I struggle to eat healthily because my friends always offer me sweets when they have them and the same with my family. I can’t talk to my family about it because they can’t understand me as they have never been through it. I think on here is the only place I can get honest answers. I am 142lbs and 5’4. I know some people might be like oh your too young to be worried about this stuff but I don’t believe I am and I feel depressed about this and it upsets me everyday and I want to make a change because I can’t live like this. Please give honest opinion but try not to make it nasty and any suggestions would be great.