Objective: This study aimed to understand COVID-19 pandemic impacts on anxiety, depression, and addictive/excessive behaviors, with exploration of intolerance of uncertainty (IU) and social connectedness as potential moderators. Participants: Adult college students participated. Method: Our online survey assessed symptoms and behaviors prior to COVID-19, during the initial outbreak (Wave 1), and during early 2021 (Wave 2). Results: Significant increases were found in anxiety, depression, binge eating, sexual behaviors, video game playing, internet/social media usage, and compulsive exercise in both waves. IU moderated the relationship between both depression/anxiety and certain excessive behaviors; social connectedness moderated the relationship between anxiety and smoking. Conclusions: This study replicated prior work and highlights new impacts on addictive/excessive behaviors, as well as moderating effects from social connectedness and IU. Future research is warranted to evaluate the efficacy of treatments targeting IU and social connectedness as the pandemic continues to unfold.