That opposites are the same thing is an idea that goes back at least as far as the ancient Greeks. Hippolytus said that the road up and the road down are the same. This is called the unity of opposites.
These days, we would say that behaviors that are apparently very different are only two sides of the same coin. In your case, you have gone from being overly empathic to being uncaring. You’ve gone from desperate attempts to help someone to playing (catfishing) with others’ feelings.
Your own analysis may be correct. Your parents didn’t provide a role model for how to manage anger or distress. They also didn’t provide you with the comfort and caring that kids need to internalize how to provide it to others. As a result, you are bouncing back and forth between the extremes, with little understanding of how to have balance in relationships.
I very much doubt that you can change this on your own. You’ve had years of “practice” with the extremes with nothing to moderate it. For that reason, I encourage you to find a therapist who specializes in work with adolescents. A therapist can hear your whole history and can help you reconsider the conclusions you reached as a child. With therapeutic encouragement and support, you can learn a more balanced and meaningful way to relate to others.
I wish you well.