Why do I vomit candy?

Whenever I eat chocolate, ice cream, cake, brownies, etc I vomit it up within 10 min. I don't eat a lot of it before I get a stomach ache. And normally I eat it about 30 min. after dinner so I'm not overeating. But not all sweets get me sick, Safeway select ice cream and Hershey's are the only brands that don't make me vomit. Is this an eating disorder? Btw I'm 12, 4'9 and 88 pounds. And I was born with eczema