Do you have any auto save or save file at all, to go back to? I recommend you save every now and again, since there's a lot of choices in this game, which can end in a game over screen/end the game, like not being prepared for that quest.
Also, if you're struggling with that fight, I recommend you buy the dagger from Bront beforehand, as it makes that fight very easy and allows you to break his shield without any effort.