Parasite

Depression has been with me for many, many years.  It is a leech that sucks the energy from my body and soul.  It has become such a part of me, like an infection or a cancer.  I look for the antidote, antibiotic or miracle cure.  It sometimes seems within my grasp but it quickly gets away from me.  It keeps me under false pretensions but still the cure alludes me.  I am in a prison and I hold the key but I cannot find the lock, it's too dark.