Huge hugs LIH. You can't help your feelings right now, but you can control your reactions and the work you do to help yourself. I went through a break up with the only man I was crazy about, and I know how terribly it can affect you.
You have the means to move on, but you have to draw on all your resources, even if you don't feel like it, or it's against your instincts. You probably need to be honest with your BF about your inability to have a healthy relationship right now. This alone will help your self-esteem.
Draw up a mind picture of the person you want to be, even if it seems unattainable right now, then break up your project into tiny steps, and go for it.