I'm thinking that it's not the break up that has caused you to become who you are but rather you were always this person but she somehow bought out the best in you until she couldn't take the negativity any longer. Your friends don't leave you to be with someone who betrayed you if you are a good friend to have. Did you invite them out to do things with you or did you just wait around to be invited? It takes being a friend to have a friend you know.
I suggest you get yourself a life coach to help you improve on your general outlook about life and yourself in general. He'll guide you to learn how to love yourself and to hone your personal boundaries which in turn will give you the confidence to be the best you that you can be.
It's time to stop blaming a breakup on why you've become who you are and do the work you need to do to overcome him. (him, of course being you as you currently are)
You can do this you just have to stop viewing yourself as some sort of victim, forget the past and look forward to who you will become.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion