Since you heard about his going away and only being in the farther office, etc. in an off-hand, indirect way; I'd wait until he told you and gave you the complete info? It may not be as bad as it ended up sounding from your source of a source's source :-) How often do you see him?

I'm with sunrise; if you end up having to change pdocs, for the first meeting I'd just take a list of what meds I'd tried and how I liked/disliked them, what I was on and a general description of my symptoms and problems. Get your life's history down to the size that will fit on one file card :-) and read it to the person whether they like it or not if that makes you more comfortable. Sometimes starting over can be a good thing, you get to "fix" things that might not have worked well for you before.