I find it often helps me to write down topics I want to talk about before a session. I may not stick to the list, but it helps organize my thoughts, and then I'm less likely to forget something important. I've had a couple "emergency sessions" with a T before, including one fairly recently. Not sure if this is going on in your head at all, but I was worried that, once I saw T, he'd be like, "I'm sorry, why did you need this extra session?" because maybe I wouldn't have seemed upset enough. But he said he wouldn't think that. (A previous one I had with ex-T, I didn't have that concern because I was clearly a wreck, and we both knew it.)

Hope it goes well and is helpful... And honestly, you could just start by saying what you said here, how it feels like everything is going wrong...