How to bring things up to your therapist when its embarrassing

I don't know how to stop thinking of therapy as embarrassing or being afraid of sharing information and having that information used against me later. I think that therapy is good and helpful, and I know I have just had bad experiences with therapy in the past, but I really want to get over this fear and just talk about what I feel and what I have experienced.

I grew up with a physically, emotionally, and mentally abusive mother. I don't have much of an issue talking about her to people because I have been able to somewhat process everything I've been through with her. I won't go into detail about every little thing, but I will talk to my therapist about with not much of a problem. I also have a lot of sexual trauma, which affects me severely now. I don't talk about it to anyone, and even typing about it right now feels like too much. When I had my first therapy session, my therapist's questions were so specific/detailed that I immediately felt like I would be too scared to talk about anything else that's currently affecting me, and it honestly made me freeze up and regret even starting therapy. But I know that if I want it to actually help me, I have to talk about it eventually.

So my question is just how would I bring these things up without feeling so embarrassed or disgusted? Or, at least, how can I bring them up while being okay with feeling that way and working through it? Because everytime I think about it I just get tight in the chest and nauseous. I normally don;t feel that way because when I go about my day I am very dissociated and almost emotionless, it's just when I think about it, or when my therapist asks me to talk about it, that is starts to feel real and affect me.