'Bellyache' is totally fictional. I like writing about things that aren't real. The song is about not trusting anyone and then putting trust in yourself and realizing that you don't know what you are doing, either. Or realizing that things you do with a group of people that you think are cool in the moment are ultimately all on you.

In this quote, Billie Eilish reflects on the fictional nature of her song "Bellyache" and the themes it explores. She explains that she enjoys writing about things that aren’t necessarily real, allowing her to express emotions and experiences that may not be directly tied to her own life but resonate with universal feelings of doubt and confusion. The song, according to Eilish, delves into the internal conflict of trusting others and eventually recognizing that personal decisions and actions are often self-directed and have consequences.

Eilish elaborates on the idea of trust in the song, explaining how the lyrics express a loss of trust in others and the realization that we may not have full control over our own decisions. The journey she describes in the song revolves around self-awareness and coming to terms with the fact that, even when surrounded by others, the responsibility for our choices ultimately falls on us. This introspection plays a key role in the song's emotional depth and the realization of how much of our experience is shaped by personal responsibility.

The quote also touches on the group dynamics that can shape one's choices. Eilish mentions how, in certain moments, we may align ourselves with people or actions that feel “cool” in the moment but later recognize that those decisions are still ours to own. This highlights a shift in perspective from external influence to a deeper personal accountability, which is a central theme in the song.

Ultimately, Eilish’s reflection on "Bellyache" reveals her ability to blend fictional storytelling with personal reflection, using music as a tool for exploring complex themes like trust, self-doubt, and the consequences of our actions. The song's underlying message encourages listeners to look inward and understand how their choices shape their experiences, even when they feel influenced by outside forces.