Kudos on your performance, that is NOT easy and you managed it very well.
I am currently studying STH and while I can play most of the song’s rhythm guitar progression, I cannot sing it at all.
While I’m playing I do have the words for the lyrics mostly going in my head, but if I try to sing it my right hand becomes immediately handicapped and I mess-up whatever strumming or fingerpicking I was attempting. Breaking the secret to play and sing has eluded me so far (need to get back to Justin’s material on that and attempt a more focused effort one day.)