Every time I eat fruit im ill the day after.............why?

I never eat fruit really. But every time ive tried to start eating it for my health i fall really ill with a cold or fever. I ate about 5 different fruits yesterday including, apple,pear,grapes,strawberries and a banana and today my throat is on fire feeling like im ready be sick and i generally feel like im just sick with a VERY soar throat. This happens EVERY time I eat fruit to be healthier, apart from that i never get ill. In fact only had a day of work when ill after eating fruit. Never ate fruit in high school and never had a single day off.