Hello,

It may be due to food. You should have mentioned exactly what food you have eaten. Some sea fish contains some toxins (Ciguatera poisoning) which can cause headache. In your case, the time between eating the suspected food and appearance of symptoms is few hours, I should say that it may be bacterial cause. Although, if time between eating the suspected food and appearance of symptoms is 12 hours or more, it may be viral cause also. But it does not seems to be a moderate food poisoning also. It may be a mild case. There is absolutely nothing to worry about.

You can do a Blood Routine Test
Some further prevention tips:
1. Wash your hands, utensils and food surfaces often. Wash your hands well with warm, soapy water before and after handling or preparing food. Use hot, soapy water to wash utensils, cutting boards and other surfaces you use. Keep raw foods separate from ready-to-eat foods. When shopping, preparing food or storing food, keep raw meat, poultry, fish and shellfish away from other foods. This prevents cross-contamination.
2. Cook foods to a safe temperature. The best way to tell if foods are cooked to a safe temperature is to use a food thermometer. You can kill harmful organisms in most foods by cooking them to the right temperature.
3.Cook ground beef to 160 F (71.1 C); steaks, roasts and chops, such as lamb, pork and veal, to at least 145 F (62.8 C). Cook chicken and turkey to 165 F (73.9 C). Make sure fish and shellfish are cooked thoroughly.
4. Refrigerate or freeze perishable foods promptly — within two hours of purchasing or preparing them. If the room temperature is above 90 F (32.2 C), refrigerate perishable foods within one hour. Defrost food safely. Don't thaw food at room temperature. The safest way to thaw food is to defrost it in the refrigerator. If you microwave frozen food using the "defrost" or "50 percent power" setting, be sure to cook it immediately.
5. Throw it out when in doubt. If you aren't sure if a food has been prepared, served or stored safely, discard it. Food left at room temperature too long may contain bacteria or toxins that can't be destroyed by cooking. Don't taste food that you're unsure about — just throw it out. Even if it looks and smells fine, it may not be safe to eat.

For now, drink plenty of water and clean foods and light diet. You can also drink some fruit juice. Antibiotic can also be taken not more than 5 days (as you have no sure shot evidence of causal organism)

Next, you should do the blood routine.

Hope I have answered your query. Let me know if I can assist you further.

Regards,
Dr. Dipan Samanta, General & Family Physician