The song "Sleep Alone" by Heart is about a woman who is feeling lonely and empty after her lover has left her. The lyrics describe her thinking about his name while alone in her car, and how a part of her feels incomplete without him. She reminisces about the love and passion he gave her, and how she longs to feel that again. The song touches on the desperation she feels, constantly waiting and counting the days until he returns to rescue her from her sadness. She daydreams and tosses and turns at night, unable to find satisfaction without him. The lyrics also talk about the addictive nature of the memories she holds onto. She finds it difficult to move on from the romance and the intense emotions that came with it. She loves reliving the love and the rush it brought, but it also afflicts her, keeping her trapped in the pain of missing him. Ultimately, the song highlights the coldness and emptiness that she feels as she spends yet another night alone, longing for her lover's presence. It emphasizes the theme that nobody is meant to sleep alone, suggesting that we all crave love and companionship. Overall, "Sleep Alone" conveys the emotions of longing, loneliness, and addiction to past love, all wrapped up in the desire for human connection and the pain of being alone.