This song is much like The Beatles' "She's Leaving Home." As in that song, we get both the woman's story and her parents' reaction. However, there are only two verses here, and one chorus. Also in that song, she is going toward her lover, and in this she is running from him.
But still, both songs are about women leaving stability for the promise of something more, even if it means instability.
While there are scant clues here, we can guess that the wedding was supposed to take place in Texas, since the color of the roses on her wedding cake recalls the song "The Yellow Rose of Texas." Also, there is a "border" so close she can drive across it in less than a day's time.
The song tells us that she feels that leaving before the wedding was the best option, the "lesser crime." Better than leaving the groom at the altar, far better than going through with the ceremony and then getting a divorce.
The word "gone" is repeated, both to imply the finality and irrevocability of her flight, and to imply the idea that she may have left not just her wedding but her senses. In short, she was stretched too tightly, and she snapped.
This is not to say that she is crazy. Having a sane reaction to an insane situation may seem crazy to all those for whom the insanity seems rational. But from her perspective, the situation was untenable, and she did what she had to do to stay sane.
Naturally, even though she feels that was she has done is for the best and will not undo it, there is still the wrenching feeling that comes with abandoning all one has known. Her dreams that night are stormy, reflecting the pain she feels, the pain she knows she has caused, and the uncertainty of tomorrow's life when she wakes.
Perhaps she associates the Mexican shoreline with "hurricane" weather, because she imagines the eye of one passing over her bed, her "pillow" an "island" targeted by the storm. Remember from the song "Hurricane Eye"-- the eye is only a temporary calm. While she is calming down from the turmoil of her leaving, the tumult of what happens tomorrow has yet to strike with its gale in turn.
The chorus explains that changes are hard, almost impossible, but so very necessary. The pain of losing everything, even if that everything is not much or even bad, keeps many people from making such changes. They stay in bad jobs or bad relationships for years or more, afraid to give up stability for potential gain. Most could give up a "no" for a "yes"... but then most such choices ask us to give up a "yes" for nothing more than a wisp of a "maybe."
And then sometimes, the present is so miserable, and the potential future that stems from it so undesirable, that this other potential future-- this thin "maybe"-- is just too alluring.
Tomorrow will bring its half of the storm, yes. But right now, in the hurricane's eye, she can see a calm sky filled with another entire "galaxy" of possibility. And if she can get through the other half of the storm, it should be clear skies after that-- containing a whole galaxy to explore as her reward.
Next Song: Once Upon a Time There Was an Ocean.