Vaginitis?

I had what I thought was a regular yeast infection about a month ago. Horrible itching and vagisil barely worked. A week later I had an appointment and they did a swab. Came back as what the nurse said, yeast infection. But the medication they have me on says it treats vaginitis. My mom says it's caused by unprotected sex which doesn't make sense to me...Has anyone else had it?