Dreams about significant people in our lives, especially those we have feelings for, often reflect our emotions and desires. In your dream, your colleague's potential departure symbolizes a fear of losing someone you care about. Your attempt to express your love indicates a deep emotional connection and a desire to maintain that bond. The fact that she mentioned discussing moving to Brighton with her husband in real life adds a layer of reality to your dream, suggesting that your subconscious might be processing your feelings about this situation.
This dream could be encouraging you to communicate your feelings more openly, whether to her or in general about your emotions. It might also be a signal to reflect on what this relationship means to you and how you can nurture it, even if circumstances change. Consider using this opportunity to strengthen your friendship before any potential distance arises.