Post-concert depression is not a clinical condition, but it can feel like a mild form of depression or sadness. Symptoms include feeling low, empty, or emotionally drained after the event, difficulty returning to normal routines or a lack of interest in enjoyable activities before the event, a strong desire to relive the experience, and a tendency to withdraw from social interactions. It’s important to distinguish these feelings from more serious mental health conditions. If these symptoms persist or significantly impair one’s ability to function daily, it may indicate a more serious issue.

Source: https://medicalchannelasia.com/life-after-coldplay-coping-with-post-concert-depression/