This text comes from The Poetical Works of Robert Burns, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
Blithe hae I been on yon hill,
As the lambs before me;
Careless ilka thought and free,
As the breeze flew over me:
Now nae langer sport and play,
Mirth or sang can please me;
Lesley is sae fair and coy,
Care and anguish seize me.
Heavy, heavy is the task,
Hopeless love declaring:
Trembling, I dow nocht but glowr,
Sighing, dumb, despairing!
If she winna ease the thraws
In my bosom swelling,
Underneath the grass-green sod
Soon maun be my dwelling.