panic at (something)
To experience an extreme or debilitating amount of fear or anxiety when presented with something. Everyone's panicking at the forecast, but I honestly don't think there's anything worth worrying about. Everything is more expensive in this city, so don't panic at the cost of dinner when they bring out the bill, OK?
panic at something
to lose control in a frightening or shocking situation. Try not to panic at what you see. It will be a shock. Don't panic at the price of food. It will be worse next week.