It is totally normal. It is a grieving process, and moving from anger to sadness and then back again is also completely normal. The final stage of grief is always acceptance. There is no timeline. It only happens when you are ready.
There are so many good responses here.... I could only suggest that the acceptance part will have to do with forgiveness. Forgiving her for all the chaos her drinking caused, forgiving the broken promises and the broken dreams, and the big one, forgiving yourself. If you are working on codependency, it can really help the forgiveness process with yourself because you will be actively seeking how to not choose to date the same types of people again. It takes a lot of inner work.
I also see in your post a lot about trust. I too have gone through the extreme of not wanting to hang out or befriend anyone who is either an alcoholic or possible codependent. It seems that everyone around is in some form of that. So I choose to keep my distance where necessary in order to keep my own stability. However, I can also now accept all of these people for who they are without also feeling the need to "fix" them. And I also know that because we are the company we keep, as I progress in my growth, I will eventually learn to start relationships with people who share my affinity for health and kindness. I am open to allowing my HP to send those people to me when I am ready.... loosely holding on ;-)