Lady Havok

I have no trouble eating yogurts, cheeses, most candies and fruits; drinking milk, sugar in coffee or tea. But; big but, I cannot eat ice cream, frozen yogurt, fruit smoothies, cake and chocolate in bar form. I know that some of these things are no-nos. But, in the off times that I eat them, I get very sick. I get sweaty, dizzy, have trouble concentrating and finishing sentences. I feeling nearly poisoned. What confuses me is that it is not consistent after 14 years. Does anyone else have similar issues?