I say all of those visions were seen because he was starting to be like his old self because he sees himself in naruto. Also it could have been like a life flashing before his eyes type thing, but just in a what if scenario.
Imho...I feel his emotions....the conflicting feelings within him were channelled into the sword thus making him want to give up imho. Had his resolve been as stable as usual imho he'd have easily destroyed their combination.