The thing to remember, is many of the people who emphatically over-share, especially on social media, are actually unhealthy, and doing so for self-validation. If you're writing to help your readers, that kind of over-sharing is "fake" truth. Stick to your reactions--how you felt about the whatever scenario, and how that realization made you feel about your current self, and most importantly, how you decided to use those feelings and realizations to improve your future self. Be as honest as you can be about those things. But the horrible thing you regret doing? That's not really relevant or necessary for your reader. Just that there was something, and you regret it. Because their circumstances won't match yours, anyway, and what they care about is not what you did, but how what you learned can help them.