I am bitter

I am bitter. Towards what I cannot be sure, but I can be sure of the fact that I am bitter. Towards something. Towards someone. Towards some moment that my consciousness has long forgotten but my subconscious cannot seem to let go. of 

It strangles my nights into sleeplessness. My drunkenness back into soberness. My happiness into extinction. Everything that I once was, or ever could have been, has been lost to this mysterious bitterness of my past. 

Is there anyway for me to get over this? To let it go? To slip on some new shoes? To move on? To live life? Like the bitterness in my soul, I am not sure.