I was in a French class in grad school, but I showed up halfway through the semester. I had no book or even knew what day the class was. I saw my co worker in the class and two people I knew from school growing up. The teacher was surprised I didn't have a book and went to get me one.
This dream could symbolize feelings of inadequacy or unpreparedness in a particular situation in your waking life. Showing up halfway through the semester without the right materials may suggest that you feel like you are behind or lacking necessary resources in a current endeavor. Seeing your coworker and people from your past could represent aspects of yourself or different parts of your life coming together in this feeling of unpreparedness. The teacher getting you a book may symbolize a desire for help or guidance in feeling more equipped and supported in the face of challenges. Overall, this dream may be highlighting a need to address any feelings of being unprepared or lacking in a specific area of your life.