I agree with journalling your feelings during the week. It helped me a lot when i first got into therapy. Some of my issues I was able to resolve by myself, just by putting everything on paper, where I could read it through. Then toward the end of the week, usually the night before, I would look at my journal and decide what topics needed to be brought up the next day.We didn't always get to all of them, but at least I had a starting point. (Put the most important ones at the top of the list.)
If you aren't used to journaling, it will take you a while to get into the habit of writing your true feelings down. But keep trying, and it will come.
Congrats on making a very important step, and going to see a therapist!