School dreams tend to surface old anxieties about being tested and measured, even years after the classroom is behind you. Showing up unprepared or lost in the hallways often points to a current situation where you feel evaluated, whether at work or in a relationship, rather than any real gap in your knowledge.
If you ignore something use Mercury because in relation with this it means renovation and growth, resolute influx and quick response. - Picatrix (Andalusia, ~1000.AD)