Why do I feel like a failure even if I somehow succeeded in life?
You are letting other people in your life tell you or make you believe you have not succeeded. YOU are the only person you can decide that you have succeeded in life. Stop trying to make others happy and just BE HAPPY with yourself today the way you are. I remember being in graduate school with my once in a lifetime job having to call my dad asking him and then finally telling him he should be proud of me. We always want approval and at some point, we just need to give to ourselves.