Song lyric: "But this half-pint imitation put me on the blink"

“Bewitched”, sung by Ella Fitzgerald and others, begins:

After one whole quart of brandy
Like a daisy, I'm awake
With no Bromo-Seltzer handy
I don't even shake

Men are not a new sensation
I've done pretty well I think
But this half-pint imitation
Put me on the blink

I'm wild again, beguiled again
A simpering, whimpering child again
Bewitched, bothered and bewildered - am I

What does the “half-pint imitation” refer to? Surely she’s not saying that her lover is a “half-pint imitation” of a man? That would not make sense, as she’s so infatuated with him.