Feeling shame is just the self-indulgence of wallowing in “I should have ___!”.
And whenever you beat yourself up over “I should have ___!”, it is simply because you are not responsibly evaluating the validity of your expectations.
Look, if you are so sure that “I should have made the right choice!” is a valid expectation, then answer the following question honestly: “Was I properly equipped to make the “right” choice back then – in terms of my mental acuity, emotional capacity & maturity, intellectual capability, experience and wisdom?”
And if you come up with the inevitable answer that “Actually, I may have been a little short on experience & wisdom back then…”, then just LET THE SHAME DISSOLVE AWAY!
PS. Learning can be a very powerful way to neutralize shame and help restore your emotional pH balance.