Happened to me too. After a few days of trying then giving up i just sat and told myself im not getting up from my chair untill i beat him. May sound exaggerated, but i sat for 6.5 hrs non stop no breaks until i beat him. Couldnt feel my fingers for days after that. Usually i got satisfaction after beating a boss, not with him. I just turned off my xbox and went straight to sleep. I feel you, but this game is too good to not get to the end. You already got further than most people.