Hi there,
You said you always read people's posts but are uncomfortable when it comes to responding. But, you see, you've just broken the ice and opened up here. That's an achievement in itself. Do you think you could just carry that over into therapy? Perhaps you could try this out here to test the waters and let us know what issues you are dealing with. See what people say. Otherwise you could, as others said, write a list and take it to therapy. Why do you think it is hard to open up to your therapist? Do you trust her enough? By all means, tell her how hard you are finding it so the two of you can explore why.