I've recently "gotten over" (I think that's probably not the best term, I've been warned it can come back at anytime quite unexpectedly for no apparent reason, but I haven't binged and purged for several months now so I'm hoping it'll stay that way) quite severe bulimia. It was something that developed over about 5 or 6 years without me even realising it and last year with a whole lot of exterior factors (like stress at work, boys, depression etc) it quickly got out of control and became the controller of my life. Like you I would miss out on functions, meeting up with friends, the whole shebang. What was even worse is that I would read about how bulimia and anorexia was screwing up other people's lives and instead of taking the cautionary tale I would pick up on the different ways they found to hide their activities and incorporate them into my life..
I know the same things don't work for everyone but my mum got me seeing a psychologist and we worked through my some of my issues. I monitored my eating and feelings in a diary, the time of my meals, binges and how I was feeling when I did it, and then if I purged, when and how it made me feel. It was tedious and very difficult as it kind of put my shame out there, because as you probably know, shame was a big part of it. In the end though I started to find links between my binges and things like perfectionism (I wanted to be perfect in everything I did but had no idea where to start, felt I should be a better person physically and emotionally etc), body issues- I knew I could look better but by classifying foods as "bad" I'd deny them and then just end up binging as well as a whole lot of other mostly typical things. I also found it helpful to read about other people (once I'd gotten over stealing their ideas) as examples. You as the outsider can recognise "oh yes, an emotional cue" or something in the person's past affecting their outcome and all the results and it sort of helps to put it all into perspective. When you're feeling ready you can make your own account and sit as the outsider and analyse your own life. You begin to notice things like silly comments people made once or twice that for some or other reason had a big impact. Like my mum saying how much better I looked after I'd lost a little weight.
That was only the first stage though, when I sort of blamed others for my issues. Eventually though I took responsibility for it and recently I haven't been associating emotions with eating or food. I think that's the most important thing. As well as learning to forgive myself if I do eat more than I should. As soon as it lost it's shame factor my problem became easier to deal with.
It also helps to tell people important in your life. My parents were incredibly supportive and my friends were even willing to distract me when I felt like I was going to binge.
Sorry this is so long but hope there's something helpful/hopeful in there for you
If there's anything more I can think of that helped me I'll keep you posted.