Your dream seems to reflect a blend of collaboration, achievement, and subsequent feelings of inadequacy or doubt. Let's break it down:

1. Group Work and Collaboration: The large group and the smaller teams indicate a desire for connection and teamwork in your waking life. You may be involved in a project or a situation where collective efforts are necessary.
2. Building and Creation: The act of building something, especially out of edible items like a gingerbread house and then "veggie people," symbolizes creativity and a sense of nurturing. This could point to a project you are passionate about or a goal you are working towards that requires your input and creativity.
3. Celebration and Recognition: Feeling like a hero and receiving celebration for your contributions suggests a yearning for appreciation and acknowledgment for your efforts in real life. This may reflect recent achievements or a desire to be validated by your peers.
4. The Trash Incident: The moment you threw away the important documents represents a fear of making mistakes or not meeting expectations. The contrast between your confidence in finding the papers and the leader's doubt may illustrate an internal conflict between your self-assurance and fears of disappointing others.
5. Feeling Like a Zero: The leader's reaction could symbolize an authority figure or a part of yourself that critiques your actions. This part of you might be highlighting your insecurities or fears about failure, especially when it comes to teamwork or collaborative efforts.

Advice: Reflect on your current collaborations and how you perceive your role within them. It's important to recognize your contributions and value, but also to understand that mistakes happen and can be opportunities for learning rather than reasons for self-doubt. Consider ways you can communicate openly with your peers about challenges and seek support if you ever feel overwhelmed. This dream encourages you to balance confidence in your abilities with a realistic understanding that setbacks are part of any collaborative process.