I know the feeling, re the blubbering. It took me weeks and weeks before I could get through the song without breaking down in the fourth verse. But there's not much point to doing a song that doesn't move you somehow, is there? I've noticed, too, that listening to someone push the words of a song past the catch in his/her throat tends to bring out a responding emotion in audiences. So don't fret until you DON'T have to deal with your feelings when doing a song...especially this one.