I'm so sorry you're going through this. About a year ago I finished therapy and it was really difficult for me to let go of my T. He was one of the most important people of my life and it hurt very much to say goodbye. We had a beautiful last session, very heartwarming and a comforting memory until this day.
The grieving was intense, it wasn't easy. I wish I could say otherwise. But I got through it and so can you. Be gentle, be nice to yourself. Cry as much as you want to but make sure to go out and have fun too. Find comfort in your gratefulness for what he has done for you. With time comes healing and strength. You can do this.