What Causes Awful Fishy Vaginal Odor?

well im a virgen but i dont know why ive been having vaginal fishy oder and a white yellow discharge for five years i recently visited my doctor but it was so werid how i had no discharge just oder so since i was a virgen they didnt do the pap test and i had to get dischrge with a cotton swab by my self but nothing came out just dry blood since i had recently been on my period will it still show any vaginal infection?