Somebody's Bonnie is on the wrong side of the sea, and the whole song is the ache of it. Bonnie is a Scots word meaning beautiful, or the beautiful one - so "my Bonnie" is simply "my darling". One old theory says the original Bonnie was Bonnie Prince Charlie, exiled over the water after 1746, and the song a coded Jacobite lament; by the time an American publisher printed it in 1881 it belonged to everyone with someone far away.
The structure is a beginner's gift: , - the same clause twice with one word swapped, then the chorus hammering the phrasal verb that matters: . Bring back, bring back, oh bring back my Bonnie to me. You could not design a cleaner drill for it.
The middle verse slips in last night as I lay on my pillow... I dreamed - the past simple telling a small sad story in two lines. Notice English says last night, never "yesterday night"; the song will remember that for you.