For a long time, mental health professionals have held on to the belief that self-esteem is a sign of ideal mental health. And yet, we are learning that there are some problems with all this emphasis on self-esteem.
SAD is not an emotion. It is Seasonal Affective Disorder (SAD). SAD is the colloquial term for an official diagnosis of Major Depressive Disorder with a Seasonal Pattern.
One of the best things you can to manage your anxiety is to focus on your breathing. There are good reasons that breathing techniques help with anxiety.
It is not unusual, at times, to feel uncomfortable or self-conscious in social settings. There are some people who are naturally shy and reserved. Social anxiety goes beyond both of these.