Governments worldwide took measures to contain the spread of the coronavirus COVID-19. Universities moved to online teaching almost overnight. This paper explores Belgian university students' perceptions, behaviors, and emotional well-being during the first weeks of strict preventive measures. We conducted a survey with 614 business administration students at the University of Antwerp. The results indicate that, in comparison to the pre-lockdown period, students feel less productive, engage less in healthy behaviors (e.g., healthy snacking, exercising alone), and report more study problems. Based on the emotional quality of their everyday experience, students can be clustered into two groups. One group (54.5%) experiences mostly negative affect, while the other reports experiencing mostly positive affect and personal optimism. The "negative affect" group consists of more women and students in the early years of their bachelor's. This group experiences more financial difficulties and spends more time on social media. These students seem to have a more challenging time coping with the lockdown: they perceive higher study load increase and more significant reduction of social contacts while facing more study problems, studying fewer hours, and perceiving a lower study efficiency. They also engage in less healthy behaviors (e.g., unhealthy snacking more, drinking more alcohol, and exercising alone less) to a greater extent than the positive affect group. These results confirm previous research, demonstrating a positive relationship between emotional well-being and the engagement in and the intensity of productive and healthy activities. Several recommendations are provided in light of these findings.