Hi I Am A 24 Yrs Old Girl. Weight =

Hi I am a 24 yrs old girl. weight = 49 kg, height = 153 cm. Staying away from home so having outside food every alternate days. Since 2 days I am having loose motions, stomach pain and fever. I started going to gym 2 days ago, is gyming the reason for my illnesses? and I haven't taken any tablet yet and have stopped having full meals, just once in a while i have bananas and coffee. Would it be okay to take a BI-Quinol ? And do I need to go see a doctor or I'll be fine with BI-Quinol?