Without the context of the poem, it's impossible to analyze the significance of the opening line. The meaning could be related to:
* Theme: The poem might be exploring the experience of Sundays, perhaps contrasting them with other days of the week.
* Tone: The use of "too" might suggest a sense of repetition, boredom, or even defiance against a routine.
* Structure: The opening line could be a deliberate choice to grab the reader's attention or set a specific rhythm.
Once you share the poem, I can offer a more specific and accurate interpretation of the opening line.