Self-tracking data is often seen as a means to reflect and achieve a goal, usually focusing on positive insights and actions. Lately, some studies have discussed the negative consequences of self-tracking, suggesting that people interact with personal data in different ways. We explored how self-tracking activities and the emotional context characterize how people engage with personal health data through the analysis of a complex and emotionally-loaded use case: Fertility self-tracking. We qualitatively analyzed patient-generated content in an online health community dedicated to fertility. We found five distinct types of engagement with data: Positive, burdened, obsessive, trapped, and abandoning. Each of them is composed of an action and an emotional component that mutually influence each other. We discuss how the interplay of these components characterize a person’s engagement with data, how the online forum made these issues visible, and how they are embedded in the self-tracking culture. We also provide insights into the implications of these issues for self-tracking tools. Finally, we hypothesize how people transition through the types of relationships with data, suggesting directions for future research in the area. Copyright is held by the owner/author(s). Publication rights licensed to ACM.