Hello I am a double board certified US doctor and I will give you a comprehensive answer.
The most likely cause of this is viral infection.
It causes nausea and diarrhea.
It will go away if this is the case.
If it does not go away, then gastritis [inflammation of the stomach or chronic ulcer
can cause both symptoms particularly in conjunction with IBS.
Your doctor also needs to rule out gallbladder, liver, and pancreatic problems, easy to do with the correct blood test.
Unless you have a family history of colon cancer at a young age: a genetic disease that runs in the family, then you do not have colon cancer.
This is a GI problem.
I am highly ranked in this area.
If your doctor is not giving you examination, testing and answers
then see a GI doctor.
I am here daily: doctor thomas.
You can save time and find me by request for safe, correct and comprehensive answers.
Please click a positive on my answer page here. Then, if you would also like to go into integrative mediicne--my other board certification--then find me by request in medical.