I am so glad to hear you are working with a psychologist that you like and trust! That is the most important thing. Don't worry about talking about the abuse, when you are ready you will do it. Maybe you won't ever talk about everything. That is OK, you can still heal and move on with your life. The important thing is that you keep working with your psychologist and keep working towards feeling better. You deserve to feel good about yourself!
I am serious. You know the abuse was not your fault, you are not a monster but your feelings of shame are real. You need to focus on getting rid of the shame and reducing your symptoms of depression. You need to work on a stronger self-esteem. Doing these things will prepare you for digging deeper with the abuse. You can not dig first. Don't worry about telling your psychologist all about what happened. That will come in time. Work on you first and keep working on a trusting relationship with your psychologist. Tell him your feelings and that you want to work on your self-esteem first. He will support you.