I went through this disease with someone close to me, and me being me, I of course researched it.
As usual with things you research I discovered the more you learn the less you know.
The more I learned the more problems presented themself.
I discovered it's difficult for a third party to get inside the sufferers barriers to help.
Also in my case by the time I figured out she had a problem, she had identified me as a threat in that I had gotten close to her.
One thing appears to be constant no matter if it is a famine, purge, feast then famine, or combination of vaireties of eating disorders. There are pschycological components, and there are a few that appear to be constant through every variety of weight loss eating disorder. Correct me if I'm wrong.
* a need to establish personal control over one's life, and the self-discipine to do it.
* Feelings of a lack of self-worth.
* A need to feel close, yet an aversion to closeness when it's recognized.
* A need to keep his or her problem secret, and a willingness to go to radical lengths to keep that secret; deception, or pushing away anyone who gets too close.
* An addictive quality to the disorder.
All these things make it difficult to help someone who is sufferering. When you get close enough to help them they're pushing you away, and, are intelligent, ordered, and tricky enough to be damn good at it.
With the girl I wanted to help, there was an added problem. Anorexia in particular appears to be prevalent amongst the last types of people you would expect to have problems, intelligent, disciplined people of a higher social strata, often with good homes, and supportive people around them.
There is another variety of the disorder though that is seen in people coming out of a dysfunctional family life. These people often have other addictive problems complicating the process. Often they feast one day then starve themselves for weeks afterwards, and sometimes purge as well. Apparently these people are the most difficult to help, and that's the problem the girl I knew had.
As for a couple of the posts I've read on this thread, in comparison I would say in the opinion of someone who's seen the thing up close, your problems (and yes it appears you do, or may have a serious problem from what you say) has some encouraging aspects.
In diffent variations you're willing to admit something's wrong, you're getting help, or thinking about it, and you appear to have a support system around you that wants to help. I would say don't be discouraged. You would appear to have a really good shot at beating this thing.