A bee in your bonnet

upset, a bit angry, on edge Aunt Betsy was kind of cranky, like she had a bee in her bonnet.

Meaning
Preoccupied or obsessed with an idea.
Origin
Thought to have come from Robert Herrick's poem, 'Mad Maid's Song', 1648.
Ah! woe is me, woe, woe is me! Alack and well-a-day!
For pity, sir, find out that bee Which bore my love away.
I'll seek him in your bonnet brave,
I'll seek him in your eyes;
Nay, now I think they've made his grave
I' th' bed of strawberries.