In this study, we compared affective ratings of emotional valence and arousal for 882 Serbian words at three points in time: before the onset of the COVID-19 pandemic (2018), during the COVID-19 lockdown (2020), and after the government measures were abandoned (2022). We did not observe a significant change in average valence or arousal ratings across time points. A more detailed look into the data revealed the change in arousal that was different across the valence values. An increase in their linear correlations and a decrease in the nonlinearity of the GAMM smooth demonstrated that, upon the onset of the COVID-19 pandemic, emotionally negative words elicited higher arousal ratings, whereas emotionally positive words elicited lower arousal ratings. It revealed that our participants became more sensitive to the negative content and less sensitive to the positive content. Our results add to the findings, which showed that the relationship between emotional valence and arousal is a function of contextual factors, which primarily influence the arousal of words.