Cybersickness remains a significant challenge for virtual reality (VR) applications, particularly in highly immersive environments. This study examined the effects of immersion, task performance, and individual differences on cybersickness symptoms across multiple stages of VR exposure. Forty-seven participants aged 18-45 completed a within-subjects design that involved the Cybersickness in Virtual Reality Questionnaire (CSQ-VR) and the Deary-Liewald Reaction Time (DLRT) task. Cybersickness symptoms were assessed across four stages: before and after VR immersion, and before and after a 12 min rollercoaster ride designed to induce cybersickness. The results showed significant increases in symptoms following the rollercoaster ride, with partial recovery during the post-ride tasks. Eye-hand coordination tasks, performed after the ride and VR immersion, mitigated nausea, as well as vestibular, and oculomotor symptoms, suggesting that task engagement plays a key role in alleviating cybersickness. The key predictors of symptom severity included a susceptibility to motion sickness and gaming experience, particularly proficiency in first-person shooter (FPS) games, which was associated with a reduced cybersickness intensity. While task engagement reduced symptoms in the later stages, particularly nausea and vestibular discomfort, overall cybersickness levels remained elevated post-immersion. These findings underscore the importance of task timing, individual differences, and immersive experience design in developing strategies to mitigate cybersickness and enhance user experiences in VR environments.