Suggest Treatment For Vaginal Infection

Hi, I am 20 years old, and have been having some issues. First I was told I had a bacterial infection, I took the medication and it went away for a while. Then the odor came back, so I went back to the dr and got more. Only this time it didn't go away. Its like this musty 'catbox' smell. I just got what I thought was a light period, and now I'm experiencing an overly sweet smell, coupled with brown discharge and slight itching and burning. I tried a monistat pack, and I havent had sex since before my last std testing at the gyno. Help please.