Thanks for posting your query at DoctorSpring.com
I am Dr.R.K and I am pleased to assist you.
You are having dyspeptic symptoms and diarrhea.
As your doctor said all these symptoms could probably be due to a stomach bug.
I would advice you to get a stool test done.
The pain you get on the left side just below the rib cage may be due to gastritis.
I would advise you to take prilosec once daily before breakfast for 4 weeks.
To relieve nausea you can zofran three times a day before food.
You can take probiotics and yogurt to get faster relief from diarrhea.
If the stool test reveals any organism, you may have to take medications to eradicate the infection.
I hope that answers your query.
Let me know if I can assist you further.