Definitely relate ! I find that these are phases in life. High phases and low phases. And sometimes feeling alive can come from different things. I was a singer once too. But now strumming my guitar and singing is not what fills me with alive-ness as it once did. I find utmost alive-ness and pleasure in other things now. Not saying that will be YOU - but that's what happened to me.
I am sure you will feel alive again. Happy and confident again. Just don't give up right now.
:)