Lost, I'd agree that it's important to communicate with her about what you're feeling. Including anger (though maybe don't express it quite the way I did with Dr. T earlier this month...).
Let her know you don't feel safe yet, that you'll need time to get there. And what might help you get there. You may not know right now, but might need to figure it out together. If you want to avoid certain topics until you get to that safe spot, also tell her that.
I will add that even though Dr. T didn't like how I went about expressing anger to him in that one session, I did feel better having gotten it out. I should have just done it in a more constructive way, but so much had built up by that point that I sort of exploded--which is very rare for me.
One thought might be to write down what you want to say and either read it or hand it to her to read (though it's awkward when they read something as we're sitting there). Or possibly email--but I know you just had an issue where she wasn't able to receive and read an email, so probably a bad option here. But I do think it can help to get all that out.