I think you could pursue two things at the same time: sorting through your inner feelings of inadequacy, and finding external activities that feel right for you.
For your inner life, find a therapist you can gel with, and talk about your emotional reactions, your past if you want to, and find alternative ways to handle your negative emotions when they occur.
For your outer life, make lists of everything that you feel some kind of "spark" for. Could be really mundane things, that just feel kind of good when you do them. Then ask yourself what it is about them that makes them feel right for you. See if there are any patterns or connections. There are plenty of online lists of questions and workbooks for people like you who are searching for what they should be doing.
There is no one thing you "should" be doing, but there will be lots of things that will be a more natural fit with your personality and natural talents. Are you more of a systematiser, who has the organisational skills to make things keep going? Or are you more comfortable with creative chaos, which can lead change in organisations and handle human complexity?
Consider hiring a coach for a couple sessions, once you have established what kind of person you are, and what qualities an occupation has to have in order to feel fulfilling to you, in order to narrow down a few choices for you to test.
This can be a very long process. Give it time, if you are serious about it, and be willing to follow a number of dead ends while you figure out what really fits (so tell that perfectionist inside you that it's ok to experiment without Achieving Tangible Success for a while!)
Good luck.