The only thing that helps forward in this situation is talking. Talking so that you can get into those child emotions in session and so that you can let the child speak in the session. If you're T is any good then she won't tell the child things that he would tell an adult, she would just talk to you as she would talk to a distressed child and in such a way she can meet some of the needs a child needs from her mother. If your T is good enough then it is wise to resist the urge to quit, because apparently there is no easier way through it anyway. You can start with someone else again but the same feelings and longing probably come again, at least you should let them come if you want to work through the pain from your childhood.

Working through transference doesn't mean intellectually talking about those things or keeping those feelings at bay by force. It really means going into those emotions with another person who symbolically takes on all those roles you transfer to her. Right now your T is your idealized mother whom you probably never had. The only way is to honestly express those emotions to her, while being in those emotions. It can take a long time but if you express your feelings long enough then eventually the pain and longing starts to dissipate.

At least that has been my experience.