Yulia Voloshyna sheltered in the Kyiv metro on Monday as Ukrainians were warned to hunker down for another massive wave of Russian attacks.
The latest series of strikes killed at least four people and saw explosions rock the capital as people were making their way to work.
Russia's defence ministry said it had carried out a mass attack on Ukraine's energy infrastructure, hitting all its targets.
"When there are explosions, I always feel a tremor. I feel my heart beat faster. It's quite difficult," said Voloshyna, a 34-year-old lawyer, who headed underground when the sirens sounded.
The latest air raid alert covered the whole country.
As the war stretches into its third year, Ukrainians like her have to strike a balance between getting on with their lives and trying to stay safe.
The capital's residents often ignore the air raid sirens that have become part of daily life, but on Monday many took shelter after the unusually loud blasts.
In the central Khreshchatyk metro station, a long escalator ride down from street level, at least 100 people were waiting for the green light from authorities.
Some had pulled out their laptops and were working on the stone steps between platforms.
A group of students sat in a circle on small chairs handed out by metro workers, sharing snacks.
Anna Bublyk, who was leaning against the wall reading her book, said she had somehow got used to the war.
"When you hear an explosion, you feel a bit uneasy, but if you worry all the time... I mean, we've been hearing these blasts for three years now," the 23-year-old said.
Svetlana Kharchenko was chatting to a woman she had just met, both sitting on folding chairs in front of the red and gold tiles decorating the station.
Kharchenko said she had arrived at the metro station at around 6.30 am (03:30 GMT) shortly after the alarm began.
"Every person who is here feels pain," she said, but "what is so disturbing is that you seem to get used to this fear".
She comes from the eastern Donetsk region, which has been a key prize for Russia since 2014, when Moscow-backed separatists tried to seize control of the Donbas region.
"No one thought that Russia, which was like our sister, would cause us such grief," she said.
"There is such a brutal war going on there," she added with tears in her eyes.
Russia has been concentrating its efforts on the eastern Donetsk region despite Ukraine's push into Kursk, partly aimed at stretching Moscow's reserves.
Voloshyna said she feared for her brother who was fighting in eastern hotspots.
"I worry about my family, friends, the whole of Ukraine, our defenders... We are always worried, we have been under stress for almost three years now," she said.
