Here is the alleged earliest copy on a slip. See the image from the Roxburghe Collection available at University College Santa Barbara EBBA ref 31429. The 1765 date is given by Ebsworth in the published collection of Roxburghe Ballads Vol 6, p240. Looking at the typography and language, I'd say it could be even earlier. It has 8 stanzas. I have later versions from the late 18th century with 9 stanzas and I'd guess none of these are the original.

The Love-sick Maid.

The Winter it is past,
And the Summer come at last;
And the small Birds sings on every Tree,
The Hearts of those is glad,
Whilst mine is very sad;
Whilst my true Love is absent from me.

I'll put on my Cap of black,
And Fringes about my Neck,
And Rings to my Fingers I'll wear;
All this I'll undertake,
For (my) true Lovers sake,
For he rides at the Curragh of Kildare.

A Livery I'll wear,
And I'll comb down my Hair,
And I'll dress in the Velvet so green,
Straitaways I will repair,
To the Curragh of Kildare,
And 'tis there I will get Tydings of him.

With Patience she did wait,
'Till they ran for the Plate,
In thinking young Johnstone to see;
But Fortune prov'd unkind,
To that Sweetheart of mine,
For he's gone to Lurgan from me.

I should not think it strange,
The wide world for to range,
If I could obtain my heart's delight.
But here in Cupid's Chains,
I'm oblig'd to remain,
Whilst in tears do spend the whole Night.

My Love is like the Sun,
That in the Firmament doth run,
Which is always constant and true.
But yours is like the Moon,
That doth wander up and down,
And in every Month it's new.

All you that are in Love,
And can or(not) it remove,
For you pittied are by me;
Experience makes me know,
That your Heart is full of woe,
Since my true Love is absent from me.

Farewel my Joy and Heart,
Since you and I must part.
You are the fairest that e'er I did see;
And I never do design,
For to alter my Mind,
Altho' you're below my Degree.

The name 'Johnston' is Scots, but there must have been plenty of Johnstons came over to Ireland. The whole style of the piece is that of the London Pleasure Gardens like Vauxhall and Ranelagh and could easily have been composed for a ballad opera there.