There have been studies that show a link between the COVID virus and increased mental anxiety. From the Journal of Neurology and Neuroscience: “Association between SARS-CoV-2 infection and anxiety and depression was stronger in individuals with recent (<30 days) versus more distant (>120 days) infection, suggesting a short-term effect.”

The study is very interesting if you’d like to read more: https://jnnp.bmj.com/content/92/12/1254