Every so often I become paranoid, anxious and obsessed with death? Cannot sleep...?

From a spiritual and intuitive perspective...it sounds like you may have experienced something either in the past or in another lifetime where this fear and anxiety has never been dealt with or cleared. Fear is only an illusion, but it will stop you in your tracks as if it is real the more energy you put towards it. To stop this cycle, you can do several things. Call upon the Divine to help you learn what it is you need to learn and ask to have this fear cleared. You can also have Reiki done (an energy clearing) from an energy healer to help initiate this process as well.