Conclusive results or not?

In october i had unprotected sex. Then i guess a few months later i had a lot of external vaginal itching. I went, it had been 4 months, to the doctor and got tested for all STD's. The guy says he tested negative and is clean. They all came back negative including the test for herpes. I went back again and he said i'm fine, he doesn't know what it is but to just use an anti-itch cream. The itching is mainly around the inner hairline. I don't have any blisters, it's just dry and itches and is a little red. My question is if the test was negative after 4 months is it safe to say i don't have herpes? Could the itching be paranoia of me thinking I have something because everytime i read a new symptom of herpes i swear i have it. Tweet