Dreams about school often symbolize learning experiences or unresolved issues from your past. Being dressed as cartoon characters suggests a playful or childlike aspect of yourself, perhaps indicating a desire to reconnect with simpler, carefree times. The advertising of the 70s replica cars may reflect nostalgia or a longing for the past, as well as a desire to showcase something you feel passionate about.

The feelings of self-doubt and thoughts of self-harm you expressed in the dream indicate a struggle with negative self-perception or mental health challenges. It's important to remember that dreams often amplify our emotions and thoughts, and they can serve as a platform to express feelings we may not address in our waking life.

The appearance of the name "Rachel" could hold significance; it might represent a part of yourself or someone from your past who embodies qualities you associate with that name. This could be an opportunity for reflection on how you view yourself or how you want to be supported by others.

Consider reaching out to supportive friends or professionals if you're feeling overwhelmed by negative thoughts. The dream suggests that you may benefit from expressing your feelings and seeking comfort in your relationships.