I had an eating disorder the entire year( and a bit of '06), and just in September I started my journey to recovery! It's tough, not going to lie. You can deny it all you want, but whoever goes through an eating disorder does have some form of depression. If you weren't depressed with your body image, you wouldn't have started your extreme dieting. I went through anorexia the longest, binging and purging only lasted for about a month or two. I tell this to anyone: you need to find someone to talk to. You can't just drop the extreme dieting, and going out and eating some fast food. It doesn't work like that, or if you do, you lose control, and go purge it all up later. If you say you're usually really happy, you may put up a wall and let no one look in, clearly what you have been doing. Don't feel like you need to tell the world that for the longest time ever you had an eating disorder, but just tell the people that matter the most, so they know the warning signs. Once you're recovered, you'll want to preach it to the world! I wish you the best of luck in recovery- it won't be easy, infact it'll be probably the hardest thing you do, but you'll feel so much better about yourself when it's all over, it'll have been worth the hell.
I'm prayin for ya :)