Guided Imagery and Music (GIM) organizes verbal preparation, guided listening, imagery exploration, and reflection into a structured, music-centered process. Existing LLM-based well-being agents remain text-centered, and emotion-aware music systems operate outside such multi-phase workflows, conditioning music on static mood descriptions. We present GIMFlow, an interactive, non-clinical GIM-inspired system that translates reflective dialogue into a structured musical trajectory through four phases: Prelude, Induction, Music Imaging, and Postlude. GIMFlow estimates current and target affective states in continuous valence-arousal space, constructs a deterministic four-waypoint transition, and maps waypoints to sections of an LLM-generated symbolic music blueprint for deterministic rendering; the system also supports metadata-based retrieval and unified session-level logging. A formative within-subject study (N=23) of the initial prototype revealed that generated music captured only the endpoint state; we then aligned waypoints with intra-piece sections and conducted a preliminary within-subject evaluation of the refined system (N=10). Results show descriptively favorable trends in valence and negative affect while positive affect and arousal are mixed; all findings are exploratory. GIMFlow is released as an open-source, installable research demonstration with example sessions and reproducible logging utilities.