My pdoc is moody. Most of the time she's so helpful and uses her experience very well. Now and then she's cold-ish and doesn't seem entirely present. There have been times when I alllmost fired her. So I understand how you're feeling, I think.
Since you've been seeing your pdoc for so many years you know each other quite well by now. If the type of behavior you've described is unusual for him, I'd tend to let his "bad day" pass. Or, if you feel like you can tell him that you found his comment about "rewriting the prescription" worrisome, let him know.
I've been seeing my pdoc for almost 4 years and once in that time I lost a written prescription. She was a bit snarly about it...apparently pdocs have to make a report when they rewrite a script. If they rewrite too many they have to pick up trash along the highway or something equally as demeaning that doesn't involve a chair to sit in.
So I'd say that if this is a one-time thing, meh...let it pass. If it's a new normal then yes, it's probably time for a fresh start.