The quote reflects a moment of introspection as the speaker experiences the changing seasons. The transition from spring and summer to autumn evokes a sense of strangeness and time passing, creating a feeling of novelty in the familiar. The phrase "it's in my head" suggests a deep, personal reflection on the nature of change and the seasons.

Autumn is depicted not just as a season but as a profound experience that resonates emotionally. The sudden shift in seasons symbolizes the passage of time and the cyclical nature of life. This realization of autumn's arrival seems to awaken the speaker to the beauty and complexity of their surroundings, highlighting how such a simple change can feel new and impactful.