I have been sick for nine days with a four day break after the first four days. stomach pain and fever. my np put me on ciprofloxacin saying it was a stomach virus but antacids give me relief. should i go back to see him?

If you are still having fever after 9 days, you definitely should go back and see your NP. The antibiotic is not the right one for your current infection and a different one may be needed. Do a COVID-19 test, too.

I might add that absence of diarrhea by this time speaks against a viral gastrointestinal tract infection. Also, antibiotics are inappropriate treatment for viral infections. I would feel more assured by your being evaluated by an MD at this time because of persistence of abdominal pain& fever.