get back, recover

I get my confidence back.

私は自信を取り戻します

I get back the confidence I had lost.

私は失っていた自信を取り戻します

I get back the confidence I had lost on the stage.

私は失っていた自信を舞台で取り戻します

I get back the confidence I had lost on the stage little by little.

私は失っていた自信を舞台で少しずつ取り戻します

I get back the confidence I had lost on the stage little by little, completely.

私は失っていた自信を舞台で少しずつ完全に取り戻します