Hi there,
I agree with Cats, that it would be best to tell them exactly what you wrote here. Maybe even print this out or write down things you want to be sure to say and bring it in. It won't sound "rehearsed", rather that there are some things that stick out for you that you want to be sure to mention. It's never too late to start feeling better, and this therapy might be the route to recovery you're looking for. I hope it goes well for you and that you'll keep us updated