At your age, I would recommend a program that will give you some structure and some instruction on how to build a healthy, well-rounded lifestyle. I truly understand your desperation, but what good will it do to lose the weight quickly through starvation, when that will only cause you to regain the weight? I PROMISE you that no one ever lost weight through a crash program and kept it off. If you don't want to spend the rest of your life yo-yoing and getting fatter and fatter over time, take an approach that keeps your nourished and allows you to lose weight gradually. If you read the maintainer's forum here -- a TERRIFIC resource -- you'll see that those folks still do EXACTLY what they did to lose weight. You need a "lifestyle makeover" that teaches you how to live the rest of your life so that you can be at a healthy weight the rest of your life. Here's what I suggest:
First of all, get out of those sweats and into real clothes. You may think you are hiding under that baggy mess, but they only make you look worse. You may not feel comfortable in spandex and belly shirts, but wearing attractive clothes that FIT will make you look and feel a LOT better. I am about the same size you are, and that's after LOSING over 150 pounds. I guarantee you that you can look nice -- even sexy -- at this size. Weight loss, even just 30 pounds, takes a lot of optimism and confidence. The negative self-image that is oozing out of your post is something that is more destructive than it is motivating. The better you feel about yourself, the more inspired you will be.
Second, look into a program like Jenny Craig (my program) or Weight Watchers. These are sane, balanced programs that take a total lifestyle approach. The idea isn't to "diet" but to learn how to manage food for the rest of your life. ALONG THE WAY you lose weight. That's the way to do it if you want to stay at a healthy weight long-term. I think that you would benefit from not only the structure of a program like this, but the guidance they offer.
Third, get moving! One of the most effective things you can do to reshape your body is exercise, both cardio AND strength training. You don't have to do anything drastic, just start walking 10 minutes per day and work up from there. Strength training is going to be VERY important to give you the hot body I know you want. There are tons of good videos (I like Kathy Smith's Lift Weights to Lose Weight series; The Firm, Tamilee Webb, Cathe Friedrich are all good too), or you can join a gym. Managing your food will get the fat off, but cardio will make you healthier overall and strength training will give you a trim, sculpted look as well as boost your metabolism, build bone health, and a million other things.
Finally, read. I highly recommend Thin for Life as a good overview of what it takes to lose weight and keep it off. You might also pick up a copy of the Dr. Phil book. I'm not a big fan of his, but this book is right on target to help deal with some of the important mental aspects of losing weight. I also encourage you to go to the maintainer's forum here and read some of the excellent posts -- there's a wealth of information there.