Hi and welcome to BW!
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It's hard to know exactly what might be bothering your LO. I'm guessing probably not the immunizations at this point, as it's been several days, and you saw her come out of the initial sleepiness/fussiness. However, it's still a possibility. I think it's more related to the WW, so something developmental, a growth spurt (has she seemed hungrier?), or just a general need for an EASY adjustment.
Can you post what a typical day looks like in EASY format? Or, possibly both what a typical day looks like and what the wonky day was as well? She may be growing out of a 3hr EASY a bit and be needing to transition to a 3.5hr routine.