...she was afraid of losing her shape, spreading out, not being able to contain herself any longer, beginning {that would be worst of all} to talk a lot, to tell everybody, to cry.
The quote highlights a deep-seated fear of losing control and identity. The character expresses anxiety about her physical and emotional states, fearing that she might expand beyond her constraints, both literally and metaphorically. This fear relates to the struggle of maintaining personal boundaries and the fear of vulnerability that often accompanies deeper emotional expression.
Additionally, the mention of talking excessively and crying points to a fear of sharing one's inner turmoil...