I'm looking for a song, kind of modern-bluegrass sounding, with lyrics as follows:

The postman stopped by
And went on his way
He dropped cards and letters
On my birthday
I almost ran through them
Till I spied one day
Just a plain greeting card
Signed just a friend

Other lyrics include things like "there's still sweet memories," "sunshine and rainbows," and "joy and pain," and "my precious darling but now just a friend."

Thanks for any help.