I know how you feel. I feel the same way. I think it's a plateau of life. You struggled so much to reach a goal and you finally reached it and it's like....where to now? I already read a lot and I try to develop/cultivate my personality but it feels like something's missing. I think it's boxing. A year ago I was full force in it and I loved my life because I was always working at something. Trying to run an extra mile, lift more, throw faster, hit harder etc. Once my school/work schedule got husky I don't have the time for it.
I guess find something like boxing was for me. Something you can immerse yourself in and compete that will keep you constantly focused on progressing. Life is spent on endeavors. Once you make money, where to now? You'll hit that plateau, especially if you hate your job.
I often wondered why those old white CEOs stay active in business till they on their deathbed even after gaining more money than they can possibly spend in their lifetime. It's about the chase. They keep reaching up and not stopping to look down to see how far they came. They just keep competing with other companies as much as they can and keep getting better at their endeavor until they die.