Dear user,
It is very commonly encountered phenomenon which you are experiencing called burn out. If you dont feel satisfaction at your work place there could be many plausible answers for the same like workplace policies, working hours, relation amongst coworkers, leadership of the place etc. Other than that a lacking sense of achievement and inner motivation could be other factors. In case have any persistent depressive or anxiety feature you could should consult a psychiatrist.
Next Steps
Try to make changes in work place, interact with coworkers, discuss with your boss, get involved in some hobbies and physical activity. If all fails try changing vocation. If you find these symptoms interrupting your work consult a psychiatrist.