Believe it or not, this has a proper word: omphaloskepsis, from Greek ‘omphalos’ meaning navel and ‘skepsis’ meaning examination.
It is often used for describing excessive time spent considering one’s own thoughts, emotions and problems. Usually it involves self-absorbed behaviour that excludes empathy for one’s fellows.
It is derived from the belief that in certain methods of meditation the practitioners were focused on their navels. It might even have some truth in it as some religious groups view the navel as the centre of life and an energy source; a powerful chakra.