On Feb. 18th, I came down with what I think was food poisoning about 2hrs. after eating at a fast food restaurant. I had diarrhea, headaches, nausea, chills, & a fever. Finally went to a Dr. Feb. 25th because I was still sick. He put me on an antibiotic, been taking it 2 days & I still have diarrhea!! Should I be concerned?