Jillian Egginton, 21, from Dundee, was working at European Metal Recycling when she took time off due to extreme morning sickness.
Miss Egginton had already been told by her doctors that her pregnancy could be difficult as she had previously had three miscarriages.
A tribunal in Glasgow heard the mum-to-be told her manager she was expecting in October, 2010. The next month, she took 11 days off because of sickness.
The following month she was ill again, but was unable to let her employer know as she had no credit on her pay-as-you-go mobile phone.
Jillian Egginton said the sickness lasted six months and was 'really bad', often occurring without warning and of a 'projectile' nature, and coming out of her nose.
The BBC reports that she told the court she 'loved' her job and 'got on well with everyone' she worked with, and 'never thought' the company would treat her as they did.
She said: "There were times when I would be in work and I would have to run outside the office so the customers didn't see me throw up.
"I never got any sick pay - I was totally broke. When I took ill in December I was unable to phone in."
Jillian was sacked in February this year for being off too many times with morning sickness and for not phoning in before 10:00 to report her absence, as per by company policy.
Miss Egginton said her sacking meant she had to move into her parents' house in Dundee as she could no longer to pay the rent for her flat.
She said: "I was utterly shocked at their decision. I had a baby on the way and I didn't know what to do. I was so stressed out.
A further hearing will be held to determine her compensation.
Miss Egginton had her baby, a little girl called Lily, in June.
Did you suffer extreme morning sickness?