I agree, mg. Except that I would say that the rhythms, the words, and the melody are all linked in a well-crafted song. Too often these days song-writers go for message over the medium, I believe.
In a perfect song all three fit together without effort so that the voice and the instruments become the vehicle and not the main attraction. In a well crafted song -- or a speech -- or a play -- the breathing should not be a problem.

olddude -- If your phrasing works out when you're not nervous I'd say you're doing OK. Keep singing, keep playing, good luck.
Cheers, Joy