I could argue both sides of this one.
You have to do what feels right to you.
However, in my 30+ year career, I've discovered that corporations have shown me little to no loyalty. Why should I show them more?
I'd say don't give up anything voluntarily, and now that you know the manager is not your friend, quit volunteering information.
The main thing you need to realize is that managing your career is up to you. Very few corporations will hold your hand and pull you up the management chain; you have to do your own climbing. Some do it through ability, others (most?) do it through back-slapping and back-stabbing.
Sometimes, you climb. Sometimes you need to find a new place to grow.