The expression “my goodness” always seemed clear to me, as it is a simple bowdlerisation of “my God”, as are many expletives. However, I have heard many times the expression “goodness me!”, which Google confirms exist (and is less used than “my Goodness”):
This expression doesn't make any sense to me on the construction. Goodness is a noun, so why is it formed that way? Is it an alteration of “my goodness”, or was it formed somewhat independently? Is it a shortening of a longer expression, which would explain its weird grammatical form?