Replying to Help on loosing weight FAST

Ok heres the deal. I've gained a TON of weight over the past few years and i finally have the incentive to loose it all. I need help though.
First off, I've started running at my local ymca and all I drink is water. I've cut all the treats out. No ice cream, cookies, brownies. None of that. I want to start a diet plan but I'm not sure what to do. If any of you guys have gone through this please help me out.

I'm 5'9 and 240. Im a fucking fat ass. And I'm 15. I want to end my last 2 years of highschool in shape and confident
If any of you could post a diet plan w/ what foods to eat that would be amazing.

Thanks ns!