How tall are you? I am in your same position. I am five eight, 17 years of age and I am quite heavy. Since I have a bigger bone structure I can't go down further than 60 kgs otherwise I would look gross..

Let me tell you, I have tried starving myself with ding more than needed exercise, and it does not work. Once you start eating again you will put the weight back on quickly. What you are doing isn't good for your health.
Some people are meant to have big boobs (Trust me, I'm 14 D) Buy an inflatable boxing bag for like 30 bucks and use it 30 min a day. I garantee your boobs will tone up and perhaps shrink.

Also cut back On sugar (Don't go crazy here!) Just bit by bit, don't punish yourself and eat 3 small meals a day. Snack on fruit through out the day.
Make a cup ofd soup and add steamed veggies into it. Also try rice crackers with a spread you enjoy.

I lost 25 kilos at the age of 14 by eating healthily and excercisng regualy. If you need any more tips, feel free to ask me

Good luck.
- Kate