1Why did nobody in the dream notice?
This version is extremely common and quietly kind. The whole panic lives in you while the crowd carries on. It is a fairly direct portrait of self consciousness — you are convinced of an audience that is not watching. People often have this one during a period of being newly visible, and it tends to mark the start of the fear loosening.
2What if I was only partly undressed?
Partial exposure usually points at a specific area rather than general shame. Missing a top can read as feelings on display; missing shoes as feeling unprepared; wearing something appropriate for the wrong occasion as being out of step with a group. Ask which part of you felt uncovered, then ask where in waking life that same part is currently visible.
3I was naked and felt completely calm. Is that strange?
Not at all, and it is a good one. Comfortable nakedness usually reads as freedom from performance — a period when you are less managed, less curated, more yourself with people. Some report it after leaving a role that required constant image control. If the dream felt like relief, believe the relief.