And concerning the titular phrase, it is seemingly meant to point to the ideological notion, as envisioned by a free-spirited person, that no day is predictable. Or let’s say that on any given day life can change.  The vocalist seems to understand, implicitly, that she’s currently going through a phase of unpredictability, one in which it appears intoxicants, both conventional and perhaps of the stronger type, are involved. And the ultimate goal in all of this is for her to truly ‘feel fine’. 

So going back to the beginning of it all, the initial assumption would be that the vocalist is unfulfilled or looking for something unspecified in life which set her out on this, shall we say unforeseeable path.