I Have Been Sick For 16 Days Now. I Went

I have been sick for 16 days now. I went to CVS's minute clinic and they prescribed me Zofran for nausea and vomiting. I finished the last tablet this morning and I still have the nausea and now I have a head ache that's almost like a migraine. I'm also having some stomach pains that range from 4 to 6. The doctor I seen said it could be viral. Should I go back to the doctor soon or is this normal.