The thing is feel your anger because it's real just like any other breakup would be. Here's the sidenote: When you are involved with an addict, you really can't believe and/or make any future plans with them because you can never tell what is real and what is fantasy. If their lips are moving, they're lying.
If you and she have broken up for good, then moving on is the best thing for you. If she just needs her space to concentrate on her sobriety, then it's good for you to give it to her. Maybe she will have room in her life once her sobriety takes root. It is for sure no easy ride once they get out of rehab. My understanding is it takes about 5 years of recovery for them to get back to the way they were before the addiction took over. I wouldn't know because I didn't stick around to find out.
I hope you can find some forgiveness for her selfishness right now. Alcoholism is a selfish disease. Recovery also has to be that way for her right now. Maybe you should be selfish too and focus your energy on taking care of yourself.
Peace,
Jen