Hi OP, this thread is active again and I hope you are reading and finding the replies helpful.
I had bulimia for most of my 20s. At the time I couldn't even imagine being free of it, but now I have been completely recovered for 15 years and never even give it a second thought anymore. I've more or less forgotten that it happened, or else feel like it happened to someone else.
I recognise a lot of what others here have said about stress factors and the need to address the psychological side. However, like you I had lots of counselling that simply didn't help because it actually failed to address the physical side. Bulimia is, after all, a behavioural disorder that has massive physical effects. The physical impact massively effects your mental health in turn, so it has to be tackled. I too reached rock bottom with where my life was headed (i.e. nowhere) and so I abandoned all the introspection and made myself address the eating problem. It meant that I had to give myself permission to eat whatever I wanted, whenever I wanted, which was the best way for me of avoiding the restrict-binge-purge cycle. My only rule was that I forbade myself from purging. This was actually the opposite of the structured programme I had been advised to follow, but I felt a lot more comfortable with it. At the start it meant that sometimes I ate too little or badly (my digestive system was very sensitive and I just wanted to eat sweets) but over time I got used to eating more normally. I binged a few times to begin with and forced myself to sit with it and not purge, which would just set the same cycle up again.
I also had to accept it when I gained weight. My weight did go up, but then it reached a natural set point (1 stone higher than I had been maintaining, BMI 23-ish) and after that it stabilised easily. It became obvious my body needed to be at that weight all along.
It took a long time but all this worked and my recovery couldn't be more complete. I also became so much more confident, alert and assertive as a person. But it was so hard to envisage a way out when I was in the grip of it, so I understand how you feel OP.
The best book I have ever read on this was Susie Orbach's 'On Eating', which gives great, simple guidance on what I have described.
Lots of love to you, OP - there is a healthy and vibrant version of you who is much closer than you think 