Dreams often reflect our subconscious thoughts, emotions, and experiences, and your dream seems to be rich with symbolism related to family dynamics, conflict, and a sense of being overwhelmed. Here are some interpretations and insights based on the elements of your dream:

1. Family Gatherings: The setting of a family gathering, particularly in a place that resembles your granny's house, suggests a desire for connection or nostalgia for family bonds. However, the presence of your dad's family, with whom you do not have a close relationship, might indicate unresolved feelings or conflicts with that side of your family.
2. Children and Relationships: The context of your children's birthday party and the presence of your children's father may signify your reflections on past relationships and how they impact your current life. The dream could be processing feelings about co-parenting, family roles, and the dynamics you experience with your children's father and his family.
3. Conflict and Tension: The argument with your children's father’s mother and the ensuing chaos represent underlying tensions or frustrations you may feel in your waking life. This could symbolize feelings of being misunderstood or not being respected within family dynamics. The fight breaking out might reflect your feelings about defending your boundaries or standing up for yourself in difficult situations.
4. Personal Well-Being: Checking on yourself in the bathroom and noticing injuries could symbolize an emotional toll that these family conflicts take on you. It may be a reminder to prioritize your own well-being amid external chaos.
5. Isolation and Support: Your struggle to find your family amidst the chaos could reflect feelings of isolation or a lack of support in your life. The request for your cousin to call the police and their reluctance may indicate feelings of frustration with others not stepping up when needed.
6. Decision to Leave: Your desire to call your mom to come get you suggests a need for escape or support. It reflects a wish to remove yourself from negative situations or people, indicating a desire for peace and resolution.

Advice: Consider reflecting on your current family dynamics and any unresolved feelings you have about your past relationships. If there are issues that need to be addressed with family members, it may be beneficial to find a constructive way to communicate your feelings. Prioritize your emotional well-being and seek support from those who can provide it. This dream could be a prompt for you to take stock of the relationships in your life and determine which ones nurture you and which ones may need to be re-evaluated.