The COVID-19 pandemic has left no one indifferent: all around the globe, people have felt the massive impact of a virus that has stopped the world in its tracks. Many countries have been forced to impose strict lockdowns, causing devastating damage to the overall economy and welfare state, but also leaving an unprecedented emotional footprint on almost everyone. In this paper, we aim to quantify, by building our own method how, this pandemic has affected people emotionally by detecting the shifts in the emotional profile of representative users in selected countries. Our method processes the social media stream adapting the Pleasure-Arousal-Dominance (PAD) approach to measure emotional states on the Russell Circumplex plane, allowing for not only an overall emotional shift quantification but also a detailed analysis at mood level. By focusing on certain emotions and searching behavior, we establish a relationship between the pandemic and the emotional response. Although the method can be applied to any location with a significant and varied amount of geo-localized social media streams, the scope of this paper covers the most representative cities in Europe.