If you say something is much ado about nothing, you think it’s an overreaction to something that shouldn’t have caused so much trouble.

Origin:

“Much Ado about Nothing” is a phrase taken from Shakespeare’s play of the same name, where characters engage in considerable drama and misinterpretation over misunderstandings and gossip. The title itself suggests that a lot of commotion is caused by something that is ultimately inconsequential. 

Synonym: a storm in a teacup and make a mountain out of a molehill.

For example:

Nancy lost her fake ring and is crying her head off. It’s such a silly thing. It’s much ado about nothing. Typical!

All this arguing is over a small mistake! Give me a break. It’s much ado about nothing.

A big fuss over a trifle, as in Jerry had everyone running around 

looking for his gloves-much ado about nothing.

After one year, I dropped out of the course because it was much ado about nothing, really. It was all about style, not about content.

Tradução: muito barulho por nada, tempestade num copo d’água.