I second Spydermonkey!

You CAN just do it. Telling youself you can't is (in a way) giving yourself permission to continue.

If you truly cannot bring yourself to stop, or you try and fail, I would question myself on what it is that bulimia gives you cannot let go of. Once you pinpoint the major reason, perhaps you can unravel the final knot that prevents you from dedicating yourself to healing.

Just as an example, I held onto bulimia because I wanted to be thin, beautiful, coveted, admired, and appreciated. Once I admitted this to myself (I denied it mentally for years, because I didn't want to admit I was so shallow) I realized I was choosing this over being a role model for my son, and that was very upsetting. In truth, I would rather he have a fat and happy mom than a thin and sick one. For me, that was my motivation and dedication factor that allowed myself to stop and never go back.

I hope you find your path, whatever it may be.