Yah, she might be expecting a call and be concerned if you don't call. Especially is you WANT to call but just aren't for no particular reason.

A better way to take a day off would be to say to her on Wednesday,..."Good night, I'll phone you on Friday..." = so that she is aware you aren't gonna phone her for a day and then you'll still get that nice little break to the pattern but offering reassurance to her at the same time.