My T and I have sat in silence for over ten minutes, sometimes.
Sometimes, I don't yet know how to answer a question we posed, or where the next important question will be. My T really believes in me setting the agenda, by talking about something - anything - that is bothering me, and then seeing where it goes. This definitely would not work for everyone, but it works really well for me and for her.
Sometimes I have just been too dissociated to do or say anything. Eventually, I spoke up and asked my T to help me come back if she thinks this is what is going on.
Would it help you to keep a piece of paper during the week with a running list of things you felt, or things you noticed, that you could bring to session to help you explore/learn what is important/helpful for you to talk about?
Would it help to ask your T to make things more structured for you?