I really need help with my weight!!!?

I've always been chubby every since I was little, but it was never an issue until I got to high school. I've always had low self-esteem because I would compare myself to the other girls. I can always randomly motivate myself to work out but I can never do a full exercise program on TV I would always stop and give up. I tried dieting but then have a less then healthy meal or I would snack all the time. I just need a really motivating person to help me I'm so self-conscious about myself its ridiculous! I ALWAYS care about what ppl think and take every word for it...if I can just lose this weight and get the body I want or just close to it ill be happy...I know I'm not the prettiest girl in the world but if I have a nice body it'll make up for it....I hope.