Just wanted to mention that this is related to the 'introject' I sometimes refer to. Just like someone projects onto/into someone else, people can introject into themselves.

An infant child is especially vulnerable to introjection; it's part of how it develops its sense of self. It's not difficult to conceptualize that we learn about who we are by how others relate to us. So, in my case, I feel that I introjected my mother's anger into me. This internalized anger actually feels 'stuck' inside me, it feels like a foreign object that actually attacks me through self-destructive behavior, etc. But it's so dissociated that I feel it's a part over which I have no control (literally); it controls me, like DID people describe. In reality I know it is a part of me, but it is not perceived that way.

I think introject might be the same thing or similar as the part self-object concept in object relations. People who have part self-object representations are often considered borderline...Intuitively, I think this is more likely to happen with pre-verbal trauma.

Anyway, I thought you might be interested in 'introject' if you are going to look into this. I also wanted to say that I think it's great that you are able to process and discharge the anger.