you sound like you have been depressed for a freakin' long time that you've associated this bleak, low, depressive state with your normal state. depression causes a vicious cycle of negative thoughts that feed and reinforce each other, making it difficult to pull yourself out of a rut. it can suck you in for years as your own thoughts and emotions lead you down even further. i would agree with @
truck that you need to look outside of yourself at this point.
what about ni? does it do anything for you?