From what you have described about yourself you have a trauma background. You should cut yourself some slack because a natural result of trauma is the desire to isolate and the development of emotional defenses that signal to others that you cannot be too close. I really empathize because I have been very avoidant all my life too. I was blind to my own defenses till I went to therapy and started taking them down bit by tiny bit. While I am certainly much better its still a struggle. I am starting to have very different types of relationships IRL now. There are some people now with whom I can be totally honest and vulnerable with. I am also more picky and I only want to be around people who can accept the real me anymore.
I think the writing is really good for you. I know it does help me to process things on the inside of me and its also fun, at least for me.