Hi. Since one of sandwich tasted funny and you still ate it indicates the cause of your symptoms are surely intestinal infection or food poisoning unless proved otherwise. Since you have vomiting, chills and diarrhea you should rush to ER for proper clinical evaluation, examination and investigations. Tests of stool and blood for electrolytes, white cell count, urea and creatinine. You may need fluid and electrolyte replacement, intravenous antibiotics and metronidazole. Once the vomiting stops then you can be started with oral therapy with a PPI like Pantoprazole, antibiotics, symptomatic and supportive therapy. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T Chandrakant, General Surgeon