Dreams like yours can be quite complex and often reflect our subconscious feelings and experiences. Here are some possible interpretations of the various elements in your dream:

1. Searching for Items: The search for a gun and fishing supplies in a sportsman's warehouse may symbolize a quest for protection or tools to tackle challenges in your life. Guns can represent power or defense, while fishing gear might indicate a desire to explore deeper emotions or capture something elusive.
2. Encountering Your Ex: Seeing your ex and her new partner can signify unresolved feelings or lingering thoughts about past relationships. The fact that you both recognized each other but didn't speak may suggest a sense of unfinished business or emotions that haven't been fully expressed.
3. Sharing Your Experience: Telling her new partner about your past with her indicates a need to assert your side of the story or validate your feelings. This could reflect a desire for closure or simply a need to process what you went through in that relationship.
4. The Dark Place: Transitioning to a dark, eerie setting may symbolize feelings of uncertainty or fear regarding your emotional state or relationships. It can represent the anxiety surrounding past experiences and the feelings of neglect or betrayal.
5. Expressing Love and Regret: Your declaration of love amidst feelings of being used as a rebound implies a conflict between your affection and the pain of past experiences. This part of the dream suggests a deep longing for connection, but also a recognition of hurt.
6. The Other Man’s Tears: His emotional state might reflect your empathy towards others who have faced similar struggles. It can also indicate a recognition of shared vulnerabilities in relationships, perhaps mirroring your own fears of abandonment or loss.
7. Rain and Urgency: The pouring rain and the pressure from friends to come inside could symbolize overwhelming emotions and the need for support from your social circle. It may also suggest a desire to retreat from uncomfortable feelings or situations.

In summary, this dream appears to encapsulate themes of love, loss, and the complexities of past relationships while navigating current emotions. It might be helpful to reflect on how these feelings manifest in your waking life and consider what steps you can take to find closure and peace regarding your past. Engaging in open conversations with your current partner about your feelings may also help you process these emotions more effectively.