Hi Erinaceous,
I just made a username here at Curezone because of your post! I relate to so much of what you have been experiencing. I think that it's really great that you're able to identify and express what you are feeling. A very good start! I'm still struggling with that myself; trying to explain and make sense of it while trying to move in a healthy direction has been very difficult.
How I came to identify and begin to develop and understanding about my own codependency is by reading. These have been very helpful for me: Codependent No More by Melody Beattie, Adult Children: The Secrets of Dysfunctional Families by John and Linda Friel, An Adult Child's Guide to What's "Normal" - also by John and Linda Friel. You can use those to help you understand origins, patterns, and how to begin to work on recovery behaviors.
After some intense reading, even more agonizing reflection, and more attempts to search for answers online, I found Codependents Anonymous 12-step meetings (CODA) listed in my local area. At my first meeting, I was so confused and still unsure if it all applied to me. I was also one of the youngest attending that night. I've gone back, and learned so much... I really encourage you to try these meetings if you haven't already!
I'll be wishing you the best! I'm also interested in your feedback.
=)