
granite1, she sees that you write words, that you express feelings and ideas in writing and in art. She wants to help you get from one form of expression to another that will be so helpful in your life.
Begin where you are. Talk about the feeling scared. Tell her in any words that come, there are no right or wrong words to speak.
You will be coloring a picture for her with your words.
I wonder if she felt disappointed that you didn't bring the letter with you because she is very interested in what you have to say, and she was excited about hearing you read it to her. It might have looked like frustration.
You could try another therapist for a few visits to see how it feels with someone else. Sometimes the therapist just isn't a good fit. You could see if it feels different with someone else.
I do not like the hospital threat in resonse to your fear about talking. Adding fear to fear is just not helpful at all. You don't need a hospital (imo), you just need patience while you find the ability to allow the words you have emerge.