Suffering From Mild Headaches, Diarrhea, Stomach Aches. Possible Reason, Time Taken To Get Relief?

Hello, i have been suffering with a illness for about 4 days now. It started on monday when during the day i felt fine with minor headaches but the late night i woke up multiple times with diarrea. The next day in continued but my forehead was very hot, the diarrea continued and i was hot and cold, all i could do was lie in bed and i didnt eat, i drunk a lot of water and took medicine for dehydration. The day after i felt a lot better but still had mild diarrea and occasionally stomach aches come. Now it is thursday and i was well enough to attend school but still get stomach aches, able to control diarrea but use the toilet more than average and is runnier than usual. Usually, it it is diarrea it shouldt last this long but i was wondering if you could inform me wether it is serious or is just a food poison/mild virus that will pass in time. I havent been sick and right now feel fine appart from the occasional stomach pains. Please could you help and try telling me what you believe it is and roughly how long it shall take to clear, thank you.