GPs have warned thousands of people across the UK are being struck down with norovirus, which causes sudden vomiting and diarrhoea.
They have urged those affected to stay off work for 48 hours after symptoms have gone to prevent the bug from spreading.
Kim McLachlan, 35, from Mobberley in Cheshire was staying at her parents' house with her husband and 14-month old son when illness struck on Boxing Day.
Her father was the first to get sick closely followed by the rest of the family.
"It's laid everybody up for a good 24 hours," she said.
My husband fell ill on New Year's Day and he's still feeling the effects now."
She said her young son dealt with it "surprisingly" well but the rest of the family suffered from aches and pains on top of the stomach upset.
"I felt very cold and feverish and my dad was very flu-like.
"You feel really awful."
Her sister has now caught the virus and she is worried her mum and mother-in-law will also fall ill.
"I've e-mailed the guys at work to say watch out for this."
Her husband, a driver who works nights, is still off work and although Kim, an engineer, has returned to the office, she says she is still feeling the effects.
"I feel very washed out and tired."
She said those affected would be wise to stay off work or it will spread through the office like wildfire.
"My advice is to drink plenty of fluids."