Hi there.
This is only my third posting on MN so bear with me as I learn to find my way around this place. (Just so you know, i'm male and I work with people who had bulimia and now no longer do).
Eating disorders in general stem from the need to have control and bulimia is surprisingly common in women (and actually in a fair number of men too). There can be many complex issues that lie at their root, from self confidence, to self control, to a coping mechanism for dealing with sexual abuse, depression and traumatic past experience.
The thing is and this is somethimes the hardest part to accept... though it may make you feel wretched in ways that only you know and I would not dream of guessing at, it is the best coping mechanism that you have got in your life right now. Does it mean that now you have started telling people about it you are feeling ready to talk about it - or is this post you feeling worse than you normally feel?
It's no shame to have the need to B&P. On top of how you feel, try not to saddle yourself with the label of an 'eating disorder' but if you can, try and summon the courage to get the help you so clearly need and want.
I wish you well. Your way of coping doesn't have to be the ONLY way. When you are ready, go look for help and you will find that one day in the not too distant future, you will be free from both the bulimia, the root causes of it and all the negative aspects that you have lived with for the last 20 years.
I wish you well. There is so much more to life than bulimia, YOU CAN be free from it once and for all, you really can.