"Very similar to shouting"? Hmmmm... that may be my problem... my high voice is ok, but it's only got mezzoforte and forte... if I try to do any less or more then it's a strain and starts cracking after a while, even if other people can't hear it, I feel it!

I sing G below middle C easily up to C above middle C. After that, it gets difficult after a while. And some days I can sing down to E below middle C, but that's rare. I hit a low D once when I had a cold, and easily, too! (I guess the vocal cords got thicker temporarily from the cold? lol.) A couple of years later I was still able to sing the A two octaves above middle C, but that's a bit out of my reach right now. My "break" is around Ab-B above middle C. (Rather clarinettish, oddly, if you take clarinet as it's written and not in concert pitch.)

Conductors always tended to prefer my high voice. It was annoying, as I have so much more flexibility and expression in the easy range. Unfortunately, that's only a bit over an octave, and most songs aren't in a good key for that.