<font color="#000088">Is it possible that you thought about having the conversation with the person, but then forgot to. And then later on, thought that you had already had the conversation with them? I've done that before, thought about talking to someone about something, and then got distracted and forgot to. Then later on I couldn't remember whether I had talked to them about it or not! Sometimes I had found out that I had talked to them about it, and didn't even remember! And other times I had forgot to!
So I know what you're talking about, I think it's just a short term memory problem. That's what I have. A problem with my short term memory! But it could be something different in your case, because everyone is different, and you are on quite a bit of medication.
I would'nt be surprised if it was a medication related thing! Or it could just be a memory thing! </font>