What an insightful letter! You’ve done half the work already. You’ve clearly outlined the problem and you seem ready to consider some changes. Without talking with you further, I can’t venture why you’ve backed away from life so utterly. I am sure that there is a good, but not very useful, reason. It’s important to get to some new understanding so that you can stop scolding yourself and instead have compassion for the younger you who came up with the best solution she could at the time. Once you know what the problem is (or was), you can turn your adult mind to finding a better way to address the problem than staying stuck in a kind of perpetual adolescence. I hope you’ll make some calls to find a therapist who can help you make sense of yourself and move forward. You are fortunate to live in a city where there are probably thousands of qualified therapists. Ask your doctor or people you trust for a referral.
The anger you are feeling is energy. You can use it either to dig your hole deeper or to jumpstart yourself into some action. I really, really hope you’ll do the latter. Get the support and help you need so that the second half of your life isn’t a repeat of the first. You deserve so much more.
I wish you well.