Your dream is rich with symbolism and seems to reflect various aspects of your life, emotions, and identity. Here’s an interpretation of some key elements:

1. School and Castle Setting: The school may symbolize a place of learning or personal development, while the castle could represent feelings of grandeur or aspiration. You might be navigating your own social hierarchies or ambitions, feeling out of place among those you perceive as 'rich' or 'royal'.
2. Family Dynamics: Having Joe Biden as your grandpa could indicate your connection to authority or leadership figures in your life. The blend of your actual family and random people may suggest a desire for recognition or belonging, as well as the complexity of your social relationships.
3. Chasing and Running Away: The lady chasing you may symbolize pressures or expectations you feel from others, while your ability to escape reflects your capability to evade those pressures. It could also suggest a fear of being overwhelmed by responsibilities or social situations.
4. Treehouse and Friends: The treehouse represents a safe space or a retreat where you can explore new friendships and identities. Meeting people from school in this setting indicates a desire for connection but also a sense of unfamiliarity with your peers.
5. Identity Changes: The shifts in your appearance and the sense of being in another body may reflect your exploration of identity, especially during transitional phases in life (like adolescence). It might suggest that you are experimenting with different aspects of yourself or feeling pressure to conform to certain roles.
6. Emotional State and Drinking: Feeling 'emo' and drinking beer can be representative of coping mechanisms you might be exploring in response to stress or anxiety. The act of throwing up could symbolize the need to release pent-up emotions or the consequences of overindulgence.
7. Location Sharing: Sharing your location with someone can signify a desire for safety and reassurance in your relationships. It reflects a need to connect and communicate, especially when feeling vulnerable.
8. Role Assignment: Seeing the paper for friend group roles suggests a subconscious concern about where you fit into social circles. The 'mom friend' role might indicate a sense of responsibility or caretaking that you feel pressured to embody.
9. Flashbacks and Soldiers: The flashbacks could represent past experiences that are influencing your current emotions or situations. Soldiers might symbolize external pressures, conflicts, or challenges you perceive in your life.

Overall, this dream may reflect your struggles with identity, social dynamics, and emotional pressures. It could be beneficial to take some time to reflect on your feelings in these areas and consider how they manifest in your waking life. Engage in self-exploration, perhaps through journaling or talking with friends, to gain clarity and understanding.