alarmed

become, get, grow

The passengers got alarmed when the plane suddenly dropped through the clouds.

(not) unduly

She wasn't unduly alarmed when her flight was delayed by a couple of hours.

at

I was alarmed at how quickly the fire spread through the old building.

by

The sudden noise in the basement alarmed the entire household by midnight.

nothing to be alarmed about

I noticed a strange noise coming from the kitchen, but my mother said there was nothing to be alarmed about.