Thank you for your query.
Nausea and vomiting during pregnancy are common.
However, your girlfriend seems to be suffering from an exaggerated form of the same, called hyperemesis gravidarum
In this condition, the nausea and vomiting worsens to the extent that normal meals cannot be retained.
You need to consult a gynecologist, as the resultant dehydration
can have negative impact on her and the growing baby.
She needs to get her complete blood count
, liver and renal profile, serum electrolytes, thyroid profile checked and an ultrasound done.
Also, she would require intravenous fluids and resuscitation
, and vitamin B 12 and doxylamine
She needs to modify her diet - have small frequent meals, avoid spicy, greasy and oily food, take bland diet, increase probiotics such as curd and yoghurt in the diet.