I wished my coworker a merry Christmas and she said “thanks have a good day”?

I didn’t expect such a dry answer.
we are friends at work
So it’s very confusing why she’s being this distant.

She has a boyfriend so I’m wondering if he’s threatened by my closeness to her

I just don’t know how to take this
Good thing I won’t see her until Jan 5th maybe the awkwardness will have faded a little

I don’t wanna lose my friendship with her and I don’t know if it’s better to address this or to pretend I didn’t notice
I wished my coworker a merry Christmas and she said “thanks have a good day”?
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