I think sometimes it can be hard to know if the anxiety is simply about change or if it's a real warning that we're about to make the wrong decision.  Maybe we have to give rational attention to what we believe is good for us, in the long-run, listen to our hearts if we can.  I'm talking here about changes caused by our own decisions.  Other change, though, is often not in our control and that's where it becomes helpful to recognize that is the case and that our task is to find whatever positives we can out of it and to manage the down sides by what we tell ourselves is going on.  Most people fight change, to some degree, because, as you said, it gets us out of our comfort zones.