HI, thanks for using healthcare magic
If you are in early pregnancy
then there may be insufficient hormone in the urine to be picked up in the test. You can consider waiting a few days and repeating it to definitively rule out pregnancy.
If this is definitively ruled out then you can look at other possible causes of nausea and vomiting.
The most common cause is viral gastroenteritis
. Bacterial gastroenteritis
is not as common as a viral cause and would be associated with more severe vomiting
Other possible causes would be food intolerance
, GERD, lesions or masses in any aspect of the gastrointestinal tract, pain, headaches, liver disease.
If your symptoms do not resolve within a few days then you can consider visiting your doctor for an assessment
I hope this helps