Not feeling good or confident after reaching goal

Hi, we’re being taught if we plan ahead of time, manage our minds, stay committed, take massive action and achieve the goal that this will build confidence.
What about when at the end of the goal there is no such outcome of feeling confident? I was largely motivated by thinking/believing that I would feel more confident once I reached my goal. I really believed that reaching the goal WOULD result in confidence.
Instead now I’m thinking I had a purpose that ended, and I feel hollow.
I’ve had this happen before too (before scholars). What is it that other people are thinking/doing when finishing their goal that gets them that confidence? Thanks.