From your symptoms, you seem to have a bacterial infection of stomach.
I suggest you first correct your dehydration. Take enough fluids, water and ORS which will combat for your lost electrolytes. I also suggest you take lime juice and coconut water. It will combat for your lost fluids and electrolytes. Dehydration signs that need IV fluids are sunken eyes, loss of turgidity of skin, confusion and weak pulse.
If you have these signs I suggest you visit a hospital immediately as you need IV fluids. You need to take amoxicillin 500 mg twice a day for 5 days and metronidazole 250 mg once a day for 5 days. If you feel that its not improving in 3 days time. it indicates you need IV antibiotics.
I suggest your main target is to maintain the lost fluid.