I guess the feeling that there needs to be a purpose, that there has to be a “goal.” I struggle with days off work, because I don’t know what I’m supposed to be doing. I worry that I’m a failure across my life, I don’t know what it means to have done my life “right.”
I know telling you not to worry is pointless, but try to realize & remember that everybody’s a failure at doing their life “right” - I can all but guarantee you not a single person has ever managed that. We all have missteps that we beat ourselves up for far too harshly.
Work goals are fine, but you should try to have personal ones, too. Anything from learning new things that will broaden your employability, to figuring out how to get ahead financially so you’ll be prepared for the unexpected and/or able to retire early if you find something else to do with your life that’s of more interest than your job. Personal goals are known to be essential to healthy mental well-being, too.
ETA: The meds someone else mentioned are also helpful if used properly. This response I gave someone else a week ago should explain what I mean.