While instructional coaching can support teacher improvement and student learning, their effectiveness and longevity in the role may be influenced by teachers' emotions, the quality of the teacher-coach relationship, as well as the cognitive and emotional climate of the school. In this study, we analyze the emotional experiences of a novice mathematics instructional coach at multiple time points over one school year, through 14 reflective interviews. We categorize the coach's descriptions of her emotions as positive, negative, and neutral and describe themes that explain why she felt the way she did in her experiences. Our analysis points to three major reasons underlying her emotional trajectory which ultimately led to her decision to discontinue her role as a coach: (a) unmet expectations (b) student learning, and (c) teacher engagement. [For the complete proceedings, see ED657822.]