Do not brood over your past mistakes and failures as this will only fill your mind with grief, regret and depression. Do not repeat them in the future.
Facebook now is mostly about people you know. In the future it could be about people you know less but are more important.
I stopped thinking about it after trying to figure out what are the lessons learned, and there are so many. After I had basically sorted that out, I figured it’s time to really look at the future and not at the past.