This study introduces an analytical framework for tracking the evolution of student discourse in online learning environments, focusing on topics and their temporal progression. Using Contextualized Topic Modeling, the study analyzed undergraduate forum messages from Fall 2019 to Spring 2020, revealing a shift from course-specific to more general topics after the pandemic's onset. By employing Word Mover's Distance, the study constructed topic chains that showed a transition from course-centric issues to broader discussions on inequities and healthcare. The findings highlight the role of online forums in reflecting changes in educational discourse and provide insights for post-pandemic higher education.