How can I lose about 70 lbs in 7 weeks?

Hi I'm 14 and 8 months. I'm 5"4 and I'm very overweight. About 230 lbs to be exact. All I want to change about me is my weight. It has been annoying me since I was about 11. I am a very happy positive and fun girl. I am however embarrassed to talk and exercise around others I would rather it be me and my I pod. I've also looked at the modified vegan diet. It follows everything a vegan would eat except you can have milk cheese and white meats. Is that a good choice maybe? If anyone has anything to help me I would love it :)))