Sometimes things change, especially in that part of the world. It actually happens on a regular basis - ports change, times change, etc. With all the unrest in Egypt, I have no doubt a lot of itineraries are going to be impacted for those traveling near that part of the world.
But your agent is not very good if he told you Princess wouldn't tell them anything without even calling them! Any time I've called and asked them about a change in itinerary, I was able to find out what happened. If your agent doesn't at least want to call and ask, then perhaps you can call Princess and see if they'll tell you what's going on.