Anonymous, what you've just described is definitely a bulimia-type eating disorder. Well done you, on revealing your demons to us, and don't feel shame for it. You're suffering this, it's not something you asked for.
Incidentally the worst possible aspect of an eating disorder is that food is both your crutch and your enemy; it's the disease and the cure. Like you said, you've determined that food has become an obsession but you have also used it as a comfort. This process of binge-purge is definitely one associated with bulimia, but the underlying issues are yet to reveal themselves completely it seems.
What you need to do is, like I mentioned before to another person, tell someone. A close family member... your GP... anyone. Let someone else into that bubble you've created. I use the metaphor again - you'll flail in the water forever until someone on the shore throws you a line to help you reel yourself in. Someone you can talk to and explain this overwhelming compulsion you have.
In many senses you need to vent the burden in open air before you yourself fully understand it. Maybe hearing it spoken out loud, you can make some revelations about why this crutch is so important and why you insist that purging is the way to "cure" yourself of the food you've been eating.
From there it's a case of slowly but surely understanding that food is a mere component of your life, not the controller. Of course I am no real role model for anyone nor should I be giving out advice given the disorder's current grip around my neck, but this is genuinely the best course of action for you.
Stay in touch on this forum. All my love, anonymous, and let us know how you proceed. Most importantly, do something TODAY. Not "soon", not "when I muster up the courage". Just do it, just take action. Or you'll always make excuses for it, you'll always be pandering to your disorder. You'll start to talk yourself out of it. And it's not worth it; trust me!