depression & running

depression is an insidious disease
it grabs me, and drags me down to where i feel there is no hope
but, i go and run, or i go to the gym, and while active, and for about an hour afterwards, i escape its clutches and feel really really good, about myself, about life. - during those moments, its like im invincible and nothing can hurt me or wear me down, stress me, pressure me, nothing.
unfortunately, it doesnt last long after finishing so i sit and am back to figuring i am lazy/fat/ugly, boring, despicable, place any self denigrating word in there and i think it of myself ...