How do you know when you're in love? All the songs make sense. Incredibly accurate You know you're in love when the first thing you think of when you wake up is... her. You know you're in love when you're doing your job or sitting at school, and realize that you're thinking about... her. You know you're in love when you hang on to every word she says, and cherish every moment you have with her. You know you're in love when you get this warm, twisting feeling in your heart whenever you talk to her. In other words, you... just know.