Sometimes I just say that I'm having trouble getting started. He's usually referred to the session notes before my appointment, so he's able to refresh my memory and we usually take it from there. Another thing that might be helpful is to just check in with yourself on how you're feeling that particular day (like, i'm feeling "anxious" or "sad" or unsettled", etc., and that can be the beginning of a great unraveling of what's going on for you.