Frequent Stomach Infections. Can i do?

Since 2 days i was heaving loose stool that were semi solid in form having 2 3 times. On 3rd night there was nausea, body shivering and 2 3 times motions. In morning i visited Gastro he said you are having stomach infection in small intestine. My concern is that in last six months 3 4 times same issues were happened and dr given infection treatment during that last year also i had these issues. I am so worried why stomach infection is happening to me again and again. Since beginning i am taking proper treatment from renowned Gastros of my area. On question that why i am having frequent infection my Dr have no answers. Pls suggest whether it is normal or what ? What can i do? Pls suggest name of any good Dr who can save my life.