I've listened many times to this:
I recognize that I may be completely wrong, and probably are (judging by how often I've misinterpreted lyrics in the past), but is not the "twist" in the final part of this song that the young woman/girl actually regrets marrying the man, and wishes that it was once again "Monday Morning", when she has not yet realized that she regrets it?
Or is it simply that the girl sings, once again, that she wishes that it was already Monday Morning, because then she will be happily married?
Is this intended to be ambiguous? Am I just an idiot who has to over-interpret or confuse simple lyrics?