depressed

Am feeling extremely depressed today. I suddenly do not know where to go in life. I feel like a total failure. Why why why why why why didn't I work harder in school? Why am I such a stupid person? Why are my grades slipping all the time? What am I doing to myself? What's wrong with me? Have all my brain cells died? What's happening to me?
 
I've been going on a downward hill for a long time. Quietly. I feel so tired, so totally disenchanted with what I've been familiar with for the most part of my life. I try my best to let go of some things, but I just can't seem to.
 
Like a bird that has lost the wind in its wings, she forgets what it was like to fly.