This dream may be a reflection of unresolved issues and negative emotions towards a particular teacher. The fact that you cannot stop thinking about this teacher suggests that there may have been significant problems between the two of you during the school year. The dream may be a manifestation of your subconscious trying to process and make sense of these difficulties. The teacher telling you that you need to talk may symbolize a desire for closure or resolution. However, the dream takes a twist when the teacher leads you to a non-existent room on the 6th floor. This could represent a false promise or deception, indicating that the teacher may not have genuine intentions to address the issues. It could also suggest that the problems you had with this teacher may not have a clear solution or resolution. Overall, this dream may be a reflection of your inner turmoil and unresolved feelings towards this teacher, and it may be a sign to confront and address these issues in order to move on and find closure.