Dreams of war can often reflect internal conflicts, stress, or feelings of instability in your waking life. The recurring theme of war in your dreams may indicate that you are grappling with significant emotional turmoil or anxiety. Here are some interpretations of the specific elements you've described:

1. Nuclear War Dream: This may symbolize fears of catastrophic change or anxiety about the future. The panic of those around you could represent feelings of helplessness or loss of control in your life. The overgrown ruins might suggest a longing for a simpler, more peaceful time or indicate the remnants of something that once was.
2. Water Gun Training: This dream could indicate that you are facing a situation that feels less serious or intense than it might appear. The absurdity of using water guns in a war context might suggest a desire to cope with conflict in a lighter way, or it could represent a feeling of being ill-prepared for a situation in your life.
3. Home Invasion by Fighters: This vivid scenario may relate to feelings of vulnerability or invasion of your personal space. It can symbolize external pressures or threats you feel in your life, whether from personal relationships, work, or societal issues. Your action of jumping out the window and hiding indicates a desire to escape or avoid confrontation.

Overall, these dreams may signify that you are experiencing heightened stress or anxiety. It could be beneficial to explore what in your waking life may be causing these feelings. Consider journaling about your emotions or discussing them with someone you trust. Finding healthy outlets for stress, such as exercise or creative activities, could also help alleviate some of the tension you're experiencing.