Does anyone feel like they are being fake in therapy? What I mean is hiding from something that is so painful you feel like your being a fake to your T?

I feel like I've been wasting my T's time for three years. There is something I want to tell her or explore in therapy and I'm so afraid to (something that's been on and off for three years in my mind). I feel like she will be disappointed or angry with me and I feel like I'm already a failure for not being more honest. In addition to that I feel like what I want to explore/talk about in therapy could ruin my life and I will be the horrible person that I feel that I am. I'm so afraid.