I'm inclined to agree. I suspect that she broke it off for professional reasons and hadn't yet found out she was pregnant. I expect the pregnancy to be the reason they get back together.
However the 18 days are enough time for her to miss a period and get worried about it, so the possibility can't be ruled out completely.
There is a rather convoluted possibility that Nora isn't pregnant, but missed a period and suspected she might be. She basically decided to be a single mom. She hadn't seen a doctor about it when she broke up with MC. In December she either gets a period or goes to a doctor who tells her that she isn't pregnant. The thing is she wanted to be and that's why she goes back to MC so he can breed her.