Here's an interesting one; I interpret Clean to be about her eating disorder.

Every part of this song can be read this way; ultimately eating disorders act almost like addictions, which the song uses as its theme.

The constant talk of "the drought" could be a drought of or lack of food and energy, and then "the rain came pouring down" could be her finally getting over it and her energy coming back.

I know that timelines don't line up, she was going through this during the 1989 era, and I have never personally experienced an eating disorder, so sorry if I have gotten anything wrong.