vaginal lips are redand sore

I had a yeast infection a few months because I had a white discharge that smelled funny. I went to the doctor and was prescribed a pill that cleared that up. I am still having irritation and itching. I went for my early check up and told my doctor about the yeast infection and how I was still having itching. She then prescribed a medicine that would clear up bacterial vaginitis. She said if the symptoms came back to see her again. They were better during the time of taking the medicine, but I still have the itching and rawness. I went back again and I was prescribed an antibiotic which doesn't seem to be helping either. My pap and cultures were done and they all come back negative.

My vaginal lips (labia) and area are very sensitive and very red. I rub them and it makes the soreness worse. I put vagisil on them and it relieves the pain. What is wrong with me? I am worried that I have an STD but I am not sure which one it could be. I have had sexual relations. Sometimes we use a condom and sometimes we don't. I have explained to my doctor that I have fooled around without a condom. She didn't seem concerned about an STD.

Please help, I am very scared!!!