Dreams involving death and tragedy can evoke strong emotions and often reflect deeper feelings or situations in your waking life. Here are some insights into your dream:

1. Setting of the School: Schools often symbolize learning, growth, and the transition from one stage of life to another. Being outside a school may suggest you are reflecting on your own education, personal development, or perhaps childhood experiences.
2. The Deaths: The presence of deceased individuals, especially when you do not know them, might represent aspects of yourself or your life that you feel are lost or changing. It can also indicate a fear of loss, whether it's related to relationships, opportunities, or personal goals.
3. Crying People: Witnessing others in grief can indicate empathy or a connection to pain and sorrow in your own life. It may also suggest that you are processing feelings of loss, whether it is about someone specific or a more generalized sense of grief.
4. Family Reunion: Meeting with family you haven’t seen in a while could symbolize a longing for connection, support, or a return to your roots. It may reflect a desire to reconnect with your past or find comfort in familiar relationships during difficult times.
5. Role of the Aunt: Your aunt leaving you with your teenage cousins could indicate feelings of responsibility or caretaking. You might be in a situation where you feel you need to support others or take on more than you feel equipped to handle.

Overall, this dream may be prompting you to explore your feelings about loss, change, and familial connections. It could be beneficial to reflect on any recent changes or challenges in your life and consider how you can seek support from loved ones. If this dream continues to trouble you, consider discussing it with someone you trust or a professional who can help you process these feelings further.