A fly's purpose

So this fly kept bugging me today.
It swirled around my head and zoomed near my eye.
I swatted it away and it retreated.
Then it reappeared by my left elbow.
It would spiral up my elbow to the flower on my shirt,
maybe recognizing it was a pretty red,
before ringing circles around my head again.
Again, I swatted it away.
Again, it retreated.
Then it came back.
How it caught up to my brisk pace I wouldn't know,
but it buzzed near me again,
and whizzed its way to my ear,
where it probably checked itself out in my cheap silver earrings.
A gift. Cheap quality, but a special gift nonetheless.
And I swatted it again, annoyed,
and when it flew to my other ear,
I ducked and swatted it more vigorously. 
Almost knocked my sunglasses on the floor.
I was fed up with the fat black fly,
who seemed to have it out for me as I walked down the street,
who seemed to want to visit me every few paces,
and thoroughly refused to leave me alone.
And, because I was by myself, I talked to that fly,
appearing even more crazy to the people walking behind me.

A girl walked up to me then,
having likely witnessed the entire fly fiasco.
She slowed down as she walked by
while the fly buzzed around my shoulder
as if it wanted to give a little fly hug. 
Her blue eyes looked into mine
and her blond hair framed her enigmatic smile.
"Careful," she said knowingly 
as I wound up for another swat. "That fly could be your grandmother."
And she walked away.

Leaving me with my outstretched hand hovering next to the fly on my shoulder,
wondering about rebirth, and afterlife,
and if that fly was really my grandmother, 
the woman I never got the chance to meet,
buzzing in to say "hi," 
fawning over her old earrings by my head 
and her favorite color on my elbow
before gently whispering, "I love you," in my ear.